Food poisoning

Signs and Symptoms of Food Poisoning

Food poisoning

Food poisoning symptoms may range from mild to severe and may differ depending on the germ you swallowed. The most common symptoms of food poisoning are:

  • Upset stomach
  • Stomach cramps
  • Nausea
  • Vomiting
  • Diarrhea
  • Fever

After you consume a contaminated food or drink, it may take hours or days before you develop symptoms. If you experience symptoms of food poisoning, such as diarrhea or vomiting, drink plenty of fluids to prevent dehydration.

When to See a Doctor for Food Poisoning

See your doctor or healthcare provider if you have symptoms that are severe, including:

  • Bloody stools
  • High fever (temperature over 102°F, measured orally)
  • Frequent vomiting that prevents keeping liquids down (which can lead to dehydration)
  • Signs of dehydration, including little or no urination, a very dry mouth and throat, or feeling dizzy when standing up
  • Diarrhea that lasts more than 3 days

Most people have only mild illnesses, lasting a few hours to several days. However, some people need to be hospitalized, and some illnesses result in long-term health problemsexternal icon or even death. Infections transmitted by food can result in:

  • Chronic arthritis
  • Brain and nerve damage
  • Hemolytic uremic syndrome (HUS) resulting in kidney failure

Some germs make you sick within a few hours after you swallow them. Others may take a few days to make you sick. This list provides the symptoms, when symptoms begin, and common food sources for germs that cause food poisoning. The germs are arranged in order of how quickly symptoms begin.

  • Symptoms begin 30 minutes – 6 hours after exposure: Nausea, vomiting, stomach cramps. Most people also have diarrhea.
  • Common food sources: Foods that are not cooked after handling, such as sliced meats, puddings, pastries, and sandwiches.
  • Symptoms begin 6 – 24 hours after exposure: Diarrhea, stomach cramps. Vomiting and fever are uncommon. Usually begins suddenly and lasts for less than 24 hours.
  • Common food sources: Beef or poultry, especially large roasts; gravies; dried or precooked foods
  • Symptoms begin 18 – 36 hours after exposure: Double or blurred vision, drooping eyelids, slurred speech. Difficulty swallowing, breathing and dry mouth. Muscle weakness and paralysis. Symptoms start in the head and move down as severity increases.
  • Common food sources: Improperly canned or fermented foods, usually homemade. Prison-made illicit alcohol.
  • Symptoms begin 1 – 4 days after exposure: Watery diarrhea, nausea. Stomach cramps, vomiting, fever, chills
  • Common food sources: Raw or undercooked shellfish, particularly oysters
  • Symptoms begin 3 – 4 days after exposure: Severe stomach cramps, diarrhea (often bloody), and vomiting. Around 5­­–10% of people diagnosed with this infection develop a life-threatening complication.
  • Common food sources: Raw or undercooked ground beef, raw (unpasteurized) milk and juice, raw vegetables (such as lettuce), raw sprouts, contaminated water
  • Symptoms begin 1 week after exposure: Watery diarrhea, loss of appetite, and weight loss. Stomach cramps/pain, bloating, increased gas, nausea, and fatigue.
  • Common food sources: Raw fruits or vegetables and herbs
  • Symptoms begin 1 – 4 weeks after exposure: Pregnant women typically experience fever and other flu- symptoms, such as fatigue and muscle aches. Infections during pregnancy can lead to serious illness or even death in newborns.Other people (most often older adults): headache, stiff neck, confusion, loss of balance, and convulsions in addition to fever and muscle aches.
  • Common food sources: Queso fresco and other soft cheeses, raw sprouts, melons, hot dogs, pâtés, deli meats, smoked seafood, and raw (unpasteurized) milk.


Food Poisoning: What to Know

Food poisoning

  • How Do You Get Sick?
  • Common Causes
  • More Serious Causes

Getting sick from eating food that has germs, viruses, or parasites is more common than you might think. An estimated 48 million Americans, that's 1 every 6, come down with food poisoning every year. Most get better on their own without medical treatment.

You may have symptoms nausea, vomiting, and diarrhea within hours of eating. But sometimes the symptoms can take days or more than a week to show up. That can make it hard to know if it's food poisoning or something else. The delay also makes it tricky to trace the illness back to the specific food or drink.

The same food can affect people differently. Some may feel unwell after just a few bites. Others can eat a lot and have no reaction at all.

Food poisoning is both more common and riskier for people with weakened immune systems, infants and young children, pregnant women, and the elderly.

Food poisoning can be caused by bacteria, viruses, or parasites. They can exist in foods at any stage, such as when they're growing, packaged, shipped, stored, or cooked.

Certain foods are more ly to harbor harmful agents. These include raw eggs, unpasteurized milk and juice, soft cheeses, and raw or undercooked meat or seafood. Fresh produce is another risk.

Foods made in bulk are problematic, too. A single bad egg could affect the whole batch of omelets in a buffet.

You could make trouble for yourself by not washing the cutting board or your hands as you prepare different foods.

Your chances of getting food poisoning are higher in the summer. In 90-degree heat, food can start to spoil within an hour.

At a picnic or during a camping trip, you are more ly to eat undercooked grilled meats or to handle raw meat without access to soap and water. Bacteria can grow quickly inside tepid coolers.

So if you're picnicking on a hot day, put leftovers back in with fresh ice.

In 4 5 cases of food poisoning, you never find out exactly what caused it. That's OK because you most ly will get better on your own. But in cases where the culprit is found, it's usually one of the following:

  • Norovirus , often called stomach flu, is behind more than half of the foodborne illnesses in the U.S. where the cause is known. Norovirus can sicken you not only through eating contaminated foods, but also through touching doorknobs and other surfaces or having contact with an infected person. You should wipe down the kitchen if someone in your house has it. It typically takes 12-48 hours before you feel sick. Your symptoms may last 1-3 days.
  • Salmonella is the name of a group of bacteria. They grow in undercooked eggs and meat. But you can also get salmonella from unpasteurized milk or cheese. Some fruits and vegetables, such as melons or sprouts, can also cause it. Symptoms start within 1-3 days and can last up to a week.
  • Clostridium perfringens are bacteria that are more ly to show up when foods are prepared in bulk, such as in cafeterias or nursing homes or for catered events. Cooking kills the bacteria but not its spores. So food left warming can grow new germs. You can get it from beef, chicken, or gravy. You may have cramps and diarrhea but no other symptoms. You get sick within 6-24 hours and are usually feeling better in a couple of days.
  • Campylobacter comes from undercooked poultry, unpasteurized milk, and sometimes water. It may take 2-5 days to develop symptoms you can notice. But you should feel better in another 2-10 days. You can't pass it to anyone. But if it's serious, you might have bloody diarrhea.

Some bacteria cause fewer cases of food poisoning but can make you very sick. They can even cause death.

They include:

  • E. coli. This is the name of a type of bacteria found in the intestines of animals. You can get this from undercooked ground beef, unpasteurized milk, sprouts, or any food or liquid that has had contact with animal feces or sewage. Some strains are harmless. Others can make you very sick.
  • Listeria is an unusual bacterium that can grow in cold temperatures such as in the refrigerator. It's found in smoked fish, raw (unpasteurized) cheeses, ice cream, pates, hot dogs, and deli meats. Pregnant women and others with weakened immune systems, can feel sick from milder infections from listeria within a day. Other people with a more serious listeria infection called listeriosis may not show symptoms for a week or even a couple of months. In addition to diarrhea and vomiting, listeria can cause unusual symptoms, including weakness, confusion, and a stiff neck. It can also be deadly. If you have a stiff neck with a fever, you may need antibiotics.

If you think you may have food poisoning, talk to your doctor.


Mayo Clinic: “Food Poisoning,” “Food Poisoning Symptoms,” “Food Poisoning: Causes.”

UpToDate: “Patient education: Food poisoning (foodborne illness) (Beyond the Basics).”

CDC: “Burden of Foodborne Illness: Findings,” “Foodborne Germs and Illnesses.”

FDA: “Foodborne Illnesses: What You Need to Know.”

U.S. Department of Agriculture: “Foodborne Illness: What Consumers Need to Know,” “Foodborne Illness Peaks in Summer — Why?” “Cooking for Groups: A Volunteer's Guide to Food Safety.” “Salmonella,” “Clostridium perfringens,” “Norovirus (Norwalk Virus),” “Campylobacter,” “E. coli,” “Listeria.”

© 2019 WebMD, LLC. All rights reserved.


Food Poisoning

Food poisoning

Food poisoning—any illness or disease that results from eating contaminated food—affects millions of Americans each year.

While the American food supply is among the safest in the world, the Federal government estimates that there are about 48 million cases of foodborne illness annually—the equivalent of sickening 1 in 6 Americans each year.

And each year these illnesses result in an estimated 128,000 hospitalizations and 3,000 deaths.

Causes of Food Poisoning

  • Bacteria and Viruses: Bacteria and viruses are the most common cause of food poisoning. The symptoms and severity of food poisoning vary, depending on which bacteria or virus has contaminated the food.
  • Parasites: Parasites are organisms that derive nourishment and protection from other living organisms known as hosts. In the United States, the most common foodborne parasites are protozoa, roundworms, and tapeworms.
  • Molds, Toxins, and Contaminants: Most food poisoning is caused by bacteria, viruses, and parasites rather than toxic substances in the food. But some cases of food poisoning can be linked to either natural toxins or added chemical toxins.
  • Allergens: Food allergy is an abnormal response to a food triggered by your body's immune system. Some foods, such as nuts, milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat or soybeans, can cause allergic reactions in people with food allergies.

Symptoms of Food Poisoning

Symptoms may range from mild to severe and differ depending on the germ you swallowed. The most common symptoms of food poisoning include:

  • Upset stomach
  • Stomach cramps
  • Nausea
  • Vomiting
  • Diarrhea
  • Fever
  • Dehydration

Serious long-term effects associated with several common types of food poisoning include:

  • Kidney failure
  • Chronic arthritis
  • Brain and nerve damage
  • Death

People at Risk

Certain groups of people are more susceptible to foodborne illness. This means that they are more ly to get sick from contaminated food and, if they do get sick, the effects are much more serious. These groups include:

  • Pregnant women
  • Children younger than 5 years
  • Adults age 65 and older
  • People whose immune systems are weakened due to illness or medical treatment

General Information

Foodborne Illness A-Z(CDC)

Foodborne Illnesses and Germs (CDC)

Foodborne Illness: What Consumers Need to Know (USDA)

Bad Bug Book (FDA)

Additional Resources

People with a Higher Risk of Food Poisoning (CDC)

Listeria– People at Risk (CDC)

Food Safety for Older Adults (FDA)

Food Safety for People with Diabetes (FDA)

Food Safety for People with Cancer (FDA)

Food Safety for People with HIV/AIDS (FDA)

Food Safety for Transplant Recipients (FDA)


How Long Does Food Poisoning Last? Causes, Symptoms & Treatment

Food poisoning

Picture of Batteria in Food

  • Food poisoning is a disease that usually results in vomiting and diarrhea after a person eats or drinks fluids contaminated with certain bacteria, viruses, parasites or chemicals (toxins).
  • The most common symptoms and signs of food poisoning are vomiting and diarrhea.
  • Other symptoms that may occur are fever, abdominal pain and/or cramps.
  • Severe signs and symptoms may include dehydration, blood in vomit or stools, diarrhea over three days, and neurologic symptoms; for example, weakness, blurry vision, and an abnormal sensation of the body such as burning, tingling, or numbness (paresthesias).
  • Causes include many things including viral and bacterial strains, parasites, and chemicals (toxins). If the cause is not from contaminated food, it most ly is contagious.
  • Depending on the cause of food poisoning, the duration of the majority of food poisoning usually ranges from a few hours after exposure to contaminated food or fluid to several days.
  • Treatment of food poisoning depends on the cause; most people self-care in a few days, but some cases may benefit from specific antibiotic or antiparasite treatments once the cause is identified.
  • Home remedies to soothe food poisoning symptoms may help speed recovery and may include:
    • Rest
    • Rehydration
    • Slowly begin to eat bland foods rice, bananas, toast, gelatin
    • Avoid alcohol, nicotine, fatty, and seasoned or spicy foods)

What Is Food Poisoning?

  • Readers Comments 28
  • Share Your Story

Food poisoning is an illness caused by eating or drinking food or water contaminated with viruses, bacteria, toxins, parasites, or chemicals. Typical symptoms of food poisoning are vomiting and diarrhea.

What Are the Signs and Symptoms of Food Poisoning?

  • Readers Comments 14
  • Share Your Story

The most common signs and symptoms of food poisoning from most causes are as follows:

  • Abdominal cramps
  • Nausea
  • Vomiting
  • Diarrhea

However, symptoms infrequently can get worse. Other symptoms include:

Symptoms of food poisoning sometimes depend on which organ system the poison effects; for example, the neurological system may be altered by neurotoxins pesticides and botulinum toxin.

When a group of individuals experiences similar symptoms after eating or drinking similar foods, food poisoning may be suspected.

Some people are at higher risk to develop food poisoning. They include children, older adults, pregnant women and people with medical conditions diabetes, liver disease, kidney disease and anyone with immunodepression.

A bagel 20 years ago was 3 inches in diameter and had 140 calories. How many calories do you think are in today's bagel? See Answer

What Causes Food Poisoning?

  • Readers Comments 11
  • Share Your Story

Viruses are the most frequent cause of food poisoning in the U.S. The next highest causes are bacteria. About 31 viral and bacterial pathogens are responsible for almost 9.

4 million diagnosed food poisoning illnesses per year; about 48 million food poisoning cases are unspecified (undiagnosed).

Yearly, about 128,000 people are hospitalized and about 3,000 die from all causes of food poisoning.

The most common pathogens that cause food poisoning are:

The most common pathogens that caused hospitalizations due to contamination of foods or fluids are:

  1. Salmonella
  2. Norovirus
  3. Campylobacter
  4. Toxoplasma gondii
  5. Escherichia coli (E. coli)

The most common pathogens that cause deaths are:

  1. Salmonella
  2. Toxoplasma gondii
  3. Listeria monocytogenes
  4. Norovirus
  5. Campylobacter

Infectious agents comprise the largest category of food poisoning, but as seen from the above top categories, viral infections comprise the bulk of infected patients but are far less ly to cause hospitalizations and deaths than Salmonella bacteria. Because the bulk of “unspecified” causes is probably similar to the makeup of the diagnosed causes, this grouping of viruses and bacteria is considered to be the main causes of food poisoning in the U.S.


There are many toxins that can cause food poisoning. Some are produced by bacteria on or in food and others are produced by plants and animals/fish or other organisms that are ingested. There are many plants and animals/fish that can be poisonous under certain conditions but they are encountered infrequently or under special conditions.

Various toxins and their sources BacteriaPlantsAnimals/fish/other
enterotoxins Mushroom toxins Scombroid toxin
exotoxins Belladona Ciguatera toxin
cytotoxins Ricin Sasitoxin
neurotoxins Hemlock Tetrodotoxin

Even though there are many bacterial, plant, and other toxins that can be ingested with food and water, they are usually limited to relatively small outbreaks.


Most parasites are ingested with contaminated food or water. Some of the parasites ingested include:

  • Giardia
  • Amoeba
  • Trichinella
  • Taenia solium


Certain chemicals are considered toxins that can cause food poisoning. Although there are over 80,000 chemicals used in the U.S., only a few have been well studied. While most do not enter into foods, some do and cause food poisoning.

An example of such a chemical is mercury, found in drinking water and in fish such as tuna and marlin. Other examples of chemicals that can be toxic if enough contaminates food and water are pesticides, polychlorinated biphenyls, and lead.

The causes of food and water poisoning are numerous. This brief listing of causes should suffice as a framework to begin more detailed studies of food poisoning.

If viruses or bacteria cause food poisoning, it can be contagious.

What Foods Cause Food Poisoning?

Foods most commonly associated with food poisoning include:

  • Eggs
  • Poultry
  • Meats
  • Unpasteurized milk or other fluids
  • Cheese,
  • Raw fruits and vegetables (usually unwashed
  • Nuts
  • Spices

How Long Does Food Poisoning Last?

In the majority of individuals with mild to moderate symptoms of food poisoning (viral and bacterial), symptoms resolve in about 24 to 48 hours and no specific medical treatment is needed.

However, if there are any signs of dehydration (decreased or no urination, dry mouth, increased thirst, dizziness, and weakness), blood in the stools, fever, vomiting or diarrhea longer than 72 hours, medical care should be sought.

If there is any reason to suspect that a rarer cause of food poisoning is causing symptoms, see a doctor.

How Is Food Poisoning Diagnosed?

The diagnosis usually begins with the patient's recent history of eating foods or exposure to contaminated water, travel history, and questions about friends or relatives with similar symptoms. The physical exam will focus on signs of dehydration and abdominal tenderness, while blood tests, if necessary, may be used to help rule out other problems.

Stool samples may be useful to detect blood in the stool, culture for pathogens, microscopically examine for parasites and to detect certain toxins. In addition, there are immunological tests for some toxins (for example, Shiga toxin). Depending on the suspected cause, in rare cases, biopsy samples may be taken.

Definitive diagnosis depends on identification of the pathogen or toxic material found in the individual.

Although tests are available, in mild to moderate cases of viral and most bacterial food poisoning, tests are not usually done because of the expense and the lihood that symptoms will resolve before the tests are completed.

What Is the Treatment for Food Poisoning?

Treatment of food poisoning is mainly done with fluids to avoid dehydration, especially in children and the elderly.

Some patients may benefit from medication to reduce nausea and vomiting.

The use of medications loperamide (Imodium) to treat diarrhea is often not advised as it may prolong symptoms or cause additional problems.

Patients are advised to check with their doctor before using the medication. Antibiotics are not used to treat viral and most bacterial causes of food poisoning but may be used in certain circumstances.

Severe bacterial infections and pregnant women with listeriosis will get antibiotics; some other pathogens such as certain parasites may be treated with antiparasitic medications. Other relatively rare causes of food poisoning may require special medications.

What Type of Diet Should I Eat After Food Poisoning?

  • Readers Comments 4
  • Share Your Story

Home care for mild to moderate bacterial and viral food poisoning is mainly preventing dehydration.

Fluid replacement by mouth using a combination of water and electrolyte solutions Gatorade or Pedialyte is usually enough to avoid dehydration as long as enough is taken to replace the amount lost through diarrhea.

Infrequent or rare causes of food poisoning should be treated by a doctor or a specialist; this should also be done in severe viral and bacterial food poisonings.

Do I Need to See a Doctor for Food Poisoning?

Although many people require no physician to intervene, a primary care physician often can treat some types of food poisonings. However, more serious types are often treated by a team that may include specialists in infectious diseases, gastroenterology, critical care, and/or toxicology.

How Do I Know If I Have Food Poisoning or the Stomach Flu?

Gastroenteritis (stomach flu) is defined as an infection or irritation of the gastrointestinal tract, especially the stomach or intestines. It is a slightly more specific term that describes a particular type of food poisoning. However, the term is used most often to describe stomach irritation or inflammation due to infection, including non-food-related infections.

How Can Food Poisoning Be Prevented?

Prevention of food poisoning is possible. The Centers for Disease Control (CDC) published ways to prevent food poisoning and included links to videos:

  • CLEAN: Wash your hands and surfaces often. Germs can survive in many places around your kitchen, including your hands, utensils, and cutting boards.
  • Rinse fresh fruits and vegetables under running water and always follow the rules of food safety.
  • SEPARATE: Don't cross-contaminate. Even after you've cleaned your hands and surfaces thoroughly, raw meat, poultry, seafood, and eggs can still spread germs to ready-to-eat foods – unless you keep them separate. Watch the SEPARATE video!
  • COOK: Cook to the right temperature. While many people think they can tell when food is “done” simply by checking its color and texture, there's no way to be sure it's safe without following a few important but simple steps. Use a food thermometer to ensure that foods are cooked to a safe internal temperature: 145 F (62.77 C) for whole meats (allowing the meat to rest for 3 minutes before carving or consuming), 160 F (71.11 C) for ground meats, and 165 F (73.89 C) for all poultry. Watch the COOK video!
  • CHILL: Keep your refrigerator below 40 F (4.44 C) and refrigerate foods properly. Germs can grow in many foods within 2 hours unless you refrigerate them. (During the summer heat, cut that time down to 1 hour.)

When traveling in foreign countries, especially developing countries, it is best to wash any fruits or vegetables before eating and only drink from commercially sealed bottles. The use of ice in drinks is not recommended.

What Is the Outlook for a Person with Food Poisoning?

Most cases of food poisoning in the U.S. have good outcomes because they usually resolve quickly and have no complications. However, in some instances, a person may have severe symptoms and the outcome may range from good to poor, depending on the person's food poisoning agent and their response to treatment.

The prognosis for common food poisoning (viral, bacterial) in developing countries is guarded especially for children and the elderly as they often have other health conditions that weaken them and sometimes have little or no access to pathogen-free foods or water.

Sleep Disorders: Foods That Help Sleep or Keep You Awake See Slideshow

The symptoms of Salmonella infections depend on the overall health of the infected person (for example, normal or with a suppressed immune system) and the particular serovar infecting the patient.

Symptoms usually begin about 12-72 hours after ingestion of the bacteria. In general, people contract S. spp (for example, serovars S. enteritidis, S.

cholerasuis) that usually cause a self-limiting diarrhea, nausea, and vomiting termed salmonellosis or S. gastroenteritis.

Read about Salmonella infection »

Reviewed on 8/28/2019


REFERENCES: CDC. “Food Safety.” Updated: Feb 07, 2018. CDC. Be Food Safe: Protect Yourself from Food Poisoning. Updated: Apr 18, 2017. CDC. “Estimates of foodborne illness in the U.S.”. Aug 19, 2016. Gamarra, R. “Food Poisoning.” Medscape. Jun 26, 2015,


Is it a Stomach Virus or Food Poisoning?

Food poisoning

By Dr. Joseph DiFranza
Family Practitioner, Reliant Medical Group

When you are vomiting every hour or going through a bad round of diarrhea, you may not care that much whether you have a stomach virus or food poisoning. However, once you recover you may wonder if you can safely return to your favorite restaurant or barbecue stand again…so it can be valuable to know the difference.

In the United States, the most common cause of a stomach virus (also known as stomach flu) is the norovirus. This is a viral infection that attacks the digestive system (and has nothing to do with the flu virus). Stomach viruses the norovirus are very contagious and can spread quickly.

We’ve all heard the stories about passengers on cruise ships suffering en masse with the norovirus. Unfortunately, people infected with a stomach virus are contagious from the moment they become ill to at least the first few days after they recover.

Typical stomach viruses can be spread in a number of ways:

  • Eating food or drinking liquids that have been contaminated with the virus
  • Touching a surface that someone with the infection has touched
  • Having direct contact with someone that has the virus

Stomach viruses can be easily spread through the vomit and stool of infected people, so caretakers should be especially careful and take precautions. Although there are rapid stool tests that can be used to detect the norovirus or rotavirus, your doctor will probably make a diagnosis by asking about your symptoms. Typical symptoms of a stomach virus (also known as gastroenteritis) are:

  • Diarrhea that may be watery or bloody
  • Nausea or vomiting
  • Stomach cramps, muscle aches or weakness
  • A low-grade fever
  • Headaches, as well as light-headedness or dizziness

Food poisoning often causes similar symptoms to a stomach virus, which is why the two conditions often confused. However, food poisoning is caused by consuming food that is contaminated by bacteria, viruses, or parasites. Medical professionals often use the term gastroenteritis to describe both conditions.

The symptoms of food poisoning hit more quickly than those of a stomach virus. While symptoms of a stomach virus can take days to develop, food poisoning symptoms can appear very quickly – within six hours of eating a meal. Food poisoning is usually caused by bacteria. Salmonella and E.

coli are two common types of bacteria linked to food poisoning. Usually food poisoning happens to more than one person at a time. (Everyone who eats the contaminated food becomes ill.

) Salad greens, eggs, undercooked poultry, dairy products and seafood can easily cause food poisoning if they are not handled properly, whether at home or in a restaurant.

Although the symptoms are similar, there are some ways to tell the difference between the stomach flu and food poisoning.

  • Bloody diarrhea is more ly to be a symptom of food poisoning.
  • Projectile vomiting and stomach cramps are often caused by the norovirus, a type of stomach virus.
  • Stomach viruses take longer to develop but usually go away in about 24 to 28 hours after symptoms begin. Food poisoning often lasts longer.
  • Food poisoning usually affects more than one person and can often be traced to a particular source.
  • A stomach virus is more ly to cause a fever, headache and stomach pain.

Whether you have food poisoning or a stomach bug, the important thing to do is treat it properly. Here are some tips:

  • One of the most important things to do is stay hydrated. Throwing up and suffering from diarrhea means you are losing a lot of fluids. Take small sips of water or broth to stay hydrated. Fluids that contain electrolytes such as sports drinks or coconut water can also be helpful (avoid sugary drinks).
  • If you can safely keep fluids in your system, you can start to eat simple, easy-to digest foods such as toast, crackers, soup, rice and bread.
  • Get plenty of rest. It’s best to cancel any planned activities until you feel better.
  • Don’t take any anti-nausea or anti-diarrhea medication without consulting a medical provider first (some medications can make you feel worse). Adults can take ibuprofen or acetaminophen to relieve symptoms.

Be sure to call your doctor if you have a fever, can’t tolerate liquids, have bloody stools or if your diarrhea is severe or lasts more than three days. If you take a prescription medication for a pre-existing condition but can’t keep it down, you should also contact your doctor.

Dr. Joseph DiFranza comes to Reliant Medical Group’s department of Family Practice in Fitchburg with over 30 years of experience in caring for patients. In addition to his work as a primary care physician he is also known around the world for his research on the addictiveness of nicotine and the health dangers of smoking.

Dr. DiFranza believes that proper care is in many ways a negotiation between the doctor and the patient. “As…

View profile View posts by this doctor


What Are the Symptoms of Food Poisoning?

Food poisoning

“Food poisoning” is a broad term that can actually cover a whole lot of different infections.

Your exact symptoms and their severity will vary. That will depend on the kind of bacteria, virus, or parasite that’s infected you, how much is in your system, and how well your immune system is fighting it off.

Despite the wide range of types, most cases of food poisoning cause some mix of the following:

If you have a mild case, you might think you have a stomach flu or virus. You may get better without any treatment. But some people have such bad symptoms that they may need to go to the hospital.

Learn more about the symptoms and when to call the doctor.

Cramps in your stomach and gut, diarrhea, and vomiting may start as early as 1 hour after eating tainted food and as late as 10 days or longer. It depends on what is causing the infection.

Some other possible, common symptoms of a variety of food poisonings might include:

  • Bloating and gas
  • Fever
  • Muscle aches
  • Weakness
  • Abdominal pain and cramping

You’ve probably heard of the some of the bad bugs that can cause food poisoning:

  • Campylobacter
  • E. coli
  • Listeria
  • Salmonella
  • Shigella

You’ve probably also heard of one of the nastiest: botulism, a rare but severe type of bacterial food poisoning. Symptoms of botulism might include:

  • Slurred speech or blurred vision
  • Muscle weakness
  • Hard time swallowing
  • Dry mouth
  • Muscle paralysis from the head down through the body
  • Vomiting

Call 911 if you see any symptoms of botulism in yourself or a loved one.

A mild case usually passes on its own with just rest and lots of fluids. You should call a doctor, however, if you or a loved one have:

  • Any signs of dehydration: dry mouth, little or no urination, dizziness, or sunken eyes
  • Any diarrhea in a newborn or infant
  • Inability to hold down liquids without vomiting
  • Diarrhea that lasts longer than 2 days (1 day in a child) or is severe
  • Severe gut pain or vomiting
  • Fever of 102 F or higher, or a rectal temperature of 100.4 F in a baby younger than 3 months 
  • Stools that are black, tarry, or bloody
  • Muscle weakness
  • Tingling in your arms
  • Blurry vision
  • Confusion
  • Diarrhea or flu illness in pregnant women
  • Jaundice (yellow skin), which can be a sign of hepatitis A


Mayo Clinic: “Food Poisoning.”

UCLA Health: “Food Poisoning.” “Symptoms of Food Poisoning.”

Kliegman, R. Nelson Textbook of Pediatrics, 19th Edition, Saunders, 2011.

National Digestive Disease Information Clearinghouse: “Diarrhea.”

Feldman, M. Sleisenger and Fordtran's Gastrointestinal and Liver Disease, 9th Edition, Saunders, 2010. “Food Poisoning,” “Fever in Infants and Children: Treatment.”

© 2019 WebMD, LLC. All rights reserved.


Food poisoning symtpoms and treatments

Food poisoning

Food can become contaminated at any stage during its production, processing or cooking.

For example, it can become contaminated by:

  • not cooking food thoroughly (particularly meat)
  • not correctly storing food that needs to be chilled at below 5C
  • keeping cooked food unrefrigerated for a long period
  • eating food that has been touched by someone who is ill or has been in contact with someone with diarrhoea and vomiting
  • cross-contamination (where harmful bacteria are spread between food, surfaces and equipment)

Cross-contamination can occur, for example, if you prepare raw chicken on a chopping board and don't wash the board before preparing food that won't be cooked (such as salad), as the harmful bacteria can be spread from the chopping board to the salad.

It can also occur if raw meat is stored above ready-to-eat meals and juices from the meat drip on to the food below.

See preventing food poisoning for information about reducing these risks

Types of infection

Food contamination is usually caused by bacteria, but it can also sometimes be caused by viruses or parasites. Some of the main sources of contamination are described below.


In the UK, campylobacter bacteria are the most common cause of food poisoning. The bacteria are usually found on raw or undercooked meat (particularly poultry), unpasteurised milk and untreated water.

The incubation period (the time between eating contaminated food and the start of symptoms) for food poisoning caused by campylobacter is usually between two and five days. The symptoms usually last less than a week.


Salmonella bacteria are often found in raw or undercooked meat, raw eggs, milk, and other dairy products.

The incubation period is usually between 12 and 72 hours. The symptoms usually last around four to seven days.


Listeria bacteria may be found in a range of chilled, “ready-to-eat” foods, including pre-packed sandwiches, cooked sliced meats and pâté, and soft cheeses (such as Brie or Camembert).

All of these foods should be eaten by their “use-by” dates. This is particularly important for pregnant women, because a listeria infection (known as listeriosis) in pregnancy can cause pregnancy and birth complications, and can result in miscarriage.

The incubation period can vary considerably, from a few days to several weeks. The symptoms will usually pass within three days.

Escherichia coli (E. coli)

Escherichia coli, often known as E. coli, are bacteria found in the digestive systems of many animals, including humans. Most strains are harmless but some can cause serious illness.

Most cases of E. coli food poisoning occur after eating undercooked beef (particularly mince, burgers and meatballs) or drinking unpasteurised milk.

The incubation period for food poisoning caused by E. coli is typically one to eight days. The symptoms usually last for a few days or weeks.


Shigella bacteria can contaminate any food that has been washed in contaminated water.

Symptoms typically develop within seven days of eating contaminated food and last for up to a week.

An infection caused by Shigella bacteria is known as bacillary dysentery or shigellosis. See the topic on dysentery for more information about it.


The virus that most commonly causes diarrhoea and vomiting is the norovirus. It's easily spread from person to person, through contaminated food or water. Raw shellfish, particularly oysters, can also be a source of infection.

The incubation period typically lasts 24-48 hours and the symptoms usually pass in a couple of days.

In young children, the rotavirus is a common cause of infection from contaminated food. The symptoms usually develop within a week and pass in around five to seven days.