Food poisoning is an
illness caused by eating foods that have harmful organisms in them. These
harmful germs can include bacteria,
viruses. They are mostly found in raw meat, chicken,
fish, and eggs, but they can spread to any type of food. They can also grow on
food that is left out on counters or outdoors or is stored too long before you
eat it. Sometimes food poisoning happens when people don't wash their hands
before they touch food.
Most of the time, food poisoning is mild
and goes away after a few days. All you can do is wait for your body to get rid
of the germ that is causing the illness. But some types of food poisoning may
be more serious, and you may need to see a doctor.
What are the symptoms?
The first symptom of
food poisoning is usually diarrhea. You may also feel sick to your stomach,
vomit, or have stomach cramps. Some food poisoning can cause a high fever and blood in your stool. How you feel when you have food poisoning mostly
depends on how healthy you are and what germ is making you sick.
If you vomit or have diarrhea a lot, you can get
dehydrated. Dehydration means that your body has lost
too much fluid.
How do harmful germs get into food?
Germs can get into food when:
Meat is processed. It is normal to find
bacteria in the intestines of healthy animals that we use for food. Sometimes
the bacteria get mixed up with the parts of those animals that we eat.
The food is watered or washed. If the water used to irrigate or
wash fresh fruits and vegetables has germs from animal manure or human sewage
in it, those germs can get on the fruits and vegetables.
is prepared. When someone who has germs on his or her hands touches the food,
or if the food touches other food that has germs on it, the germs can spread.
For example, if you use the same cutting board for chopping vegetables and
preparing raw meat, germs from the raw meat can get on the vegetables.
How will you know if you have food poisoning?
Because most food poisoning is mild and goes
away after a few days, most people don't go to the doctor. You can usually
assume that you have food poisoning if other people who ate the same food also
If you think you have food poisoning, call your local
health department to report it. This could help keep others from getting sick.
Call your doctor if you think you may have a serious illness. You may need to see your doctor if
your diarrhea or vomiting is very bad or if you don't start to get better
after a few days.
If you do go to
the doctor, he or she will ask you about your symptoms (diarrhea, feeling sick
to your stomach, or throwing up), ask about your health in general, and do a
physical exam. Your doctor will ask about where you have been eating and
whether anyone who ate the same foods is also sick. Sometimes the doctor will
take stool or blood samples and have them tested.
How is it treated?
In most cases, food poisoning goes away on
its own in 2 to 3 days. All you need to do is rest and get plenty of fluids to
dehydration from diarrhea. Drink a cup of water or rehydration drink
(such as Pedialyte) each time you have a large, loose
stool. Soda and fruit juices
have too much sugar and shouldn't be used to rehydrate.
Antibiotics usually aren't used to
treat food poisoning. Medicines that stop diarrhea (antidiarrheals) can be
helpful, but they should not be given to infants or young children. You shouldn't take antidiarrheals if you have a high fever or have blood in the diarrhea, because they can make your illness worse.
If you think you are severely dehydrated, you may need to go to the
How can you prevent food poisoning?
You can prevent most cases of food poisoning
with these simple steps:
Clean. Wash your hands often and always before
you touch food. Keep your knives, cutting boards, and counters clean. You can
wash them with hot, soapy water, or put items in the dishwasher and use a
disinfectant on your counter. Wash fresh fruits and
Separate. Keep germs from raw meat from getting on
fruits, vegetables, and other foods. Put cooked meat on a clean platter, not
back on the one that held the raw meat.
Cook. Make sure that meat,
chicken, fish, and eggs are fully cooked.
leftovers right away. Don't leave cut fruits and vegetables at room temperature
for a long time.
When in doubt, throw it out. If you aren't sure
if a food is safe, don't eat it.
Frequently Asked Questions
Learning about food poisoning and safe food handling:
is an illness caused by eating or drinking contaminated food. You
can get food poisoning by eating food contaminated by harmful organisms, such
as bacteria, parasites, and viruses.
The most common ways that
harmful organisms are spread are:
During food processing. It is normal to find
bacteria in the intestines of healthy animals that we use for food. If bacteria
come in contact with meat or poultry during processing, they can contaminate
the food. Campylobacter, salmonella, and
E. coli are often spread in
this way. In one test, campylobacter was found in almost half of the raw chicken
During food growing. Fresh fruits and vegetables can be
contaminated if they are washed or irrigated with water that is contaminated
with animal manure or human sewage. Staph food poisoning, E. coli, and shigellosis are often spread through contaminated
During food handling. Food can be contaminated when an
infected person handles the food or if it comes in contact with another
contaminated product. For example, if you use the same cutting board for both
chopping vegetables and preparing raw meat, you risk contaminating the
Through the environment. Many harmful organisms that
are commonly found in dirt, dust, and water can find their way into the foods
we eat. These organisms include Clostridium perfringens and
Cryptosporidium parvum. Environmental conditions—such
as water polluted by farm runoff—may make this type of infection more
frequent. Home-canned foods that have not been prepared properly may contain another organism, Clostridium botulinum.
The symptoms of
food poisoning usually affect your stomach and
intestines (gastrointestinal tract).
The first symptom is usually
Other symptoms include feeling sick to your stomach
(nausea), vomiting, and abdominal (belly) cramps.
The time it takes for symptoms to appear, how severe the
symptoms are, and how long the symptoms last depend on the infecting organism,
your age, and your overall health.
The very young and the very
old may be most affected by food poisoning. Their symptoms may last longer, and
even the types of food poisoning that are typically mild can be
life-threatening. This may also be true for pregnant women and people with
impaired immune systems, such as those who have
long-lasting (chronic) illnesses.
Not all food poisoning causes diarrhea, nausea, vomiting, and belly cramps. Some types of food
poisoning have different or more severe symptoms. These can include weakness,
numbness, confusion, or tingling of the face, hands, and feet.
Gastrointestinal symptoms, such as diarrhea and vomiting,
can also be caused by organisms that aren't necessarily spread through food.
These organisms are mainly spread through water or personal contact.
Conditions caused by these organisms include infection
with the parasite Giardia lamblia.
Learn more about specific food poisoning organisms, including how they are spread, their symptoms, and their treatment:
You may become ill with
food poisoning after you eat food that contains
bacteria, viruses, or other harmful organisms. Most cases of food poisoning
follow the same general course.
After you eat a contaminated
food, there is an hours-to-days delay before you notice symptoms. The
contaminating organism passes through the stomach into the intestine, attaches
intestinal walls, and begins to multiply. Some
organisms stay in the intestine. Some produce a toxin that is absorbed into the
bloodstream. And others directly invade body tissues. Your symptoms depend
greatly on the type of organism that has infected you.
organisms cause similar symptoms, especially diarrhea, vomiting, and stomach
cramps. Diarrhea and vomiting are a normal response as the body tries to rid
itself of harmful organisms. Unless the illness is part of a recognized
outbreak, it's difficult to identify the infecting organism. Lab
tests usually aren't done.
In most cases, you recover in a few
days to a week as toxins are flushed from your system. You may feel weak for
several days after other symptoms go away.
Most of the time, food
poisoning is mild and passes in a few days. But the symptoms and course of some
types of food poisoning may be more severe. To learn more, see Symptoms for a list of specific organisms.
In rare cases, food poisoning can result in kidney or joint
What Increases Your Risk
People at increased risk of
becoming ill with
food poisoning and of having more severe symptoms
Call 911 or other emergency services right away if:
You have signs of severe dehydration. These
include little or no urine; sunken eyes, no tears, and a dry mouth and tongue;
fast breathing and heartbeat; feeling very dizzy or lightheaded; and not
feeling or acting alert.
You think you may have food poisoning
from a canned food and you have symptoms of botulism (blurred or double vision,
trouble swallowing or breathing, and muscle weakness).
Call your doctor immediately if:
You have severe diarrhea (large amounts of loose stool every 1 to
2 hours) that lasts longer than 2 days if you are an adult.
have vomiting that lasts longer than 1 day if you are an adult.
You have symptoms of mild dehydration (dry
mouth, dark urine, not much urine) that get worse even with home treatment.
You have a fever.
You aren't feeling better after 1
week of home treatment.
If you think you have eaten contaminated food, your local
Poison Control Center can answer questions and provide information on what to
do next. Poison Control Centers are usually listed with other emergency numbers
in your telephone book.
Children, pregnant women, and people with
long-lasting (chronic) conditions, such as
diabetes, are more likely to have severe dehydration
and should be watched closely for symptoms.
Watchful waiting is a period of time during
which you and your doctor observe your symptoms or condition
without using medical treatment.
Watchful waiting may be appropriate if you
have diarrhea, stomach cramps, and other symptoms of stomach flu (gastroenteritis). Most people recover from these
gastrointestinal illnesses at home in several days without medical treatment.
Likewise, some cases of bacterial food poisoning are mild and pass in several
days. But if diarrhea is severe or lasts longer than a week, call your
doctor for advice.
Who to see
Health professionals who are able to diagnose and treat food
food poisoning is mild and passes in a few days, so most
people don't go to a doctor for a diagnosis. You can often
diagnose food poisoning yourself if others who ate the same food as you also
If you do go to your doctor, he or she
will make the diagnosis based on your symptoms, a physical exam, and your
medical history. Your doctor will ask
where you have been eating and whether anyone who ate the same food has the
Sometimes the following tests are done:
stool culture may be done if your doctor
suspects that you have eaten contaminated food, your symptoms are severe, or
the diagnosis is uncertain.
Blood tests may be done to help
find out whether the food poisoning is caused by bacteria or to rule out other
complete blood count and a
chemistry screen can help show whether you are
severely ill or dehydrated.
To learn more about treating dehydration, including in children, see Home Treatment.
The goal of treatment is to replace fluids and
electrolytes lost through vomiting and diarrhea. If
dehydration is severe and can't be managed at home, you may need treatment in
the hospital, where fluids and electrolytes may be given to you by inserting a
needle into your vein (intravenously).
Medicines that stop diarrhea (such as Imodium) can
help with your symptoms. But these medicines shouldn't be used in children or
in people with a high fever or bloody diarrhea.
Antibiotics are rarely used and only for certain types
of food poisoning or in severe cases.
Pregnant women with
toxoplasmosis may receive antibiotics.
information on treating diarrhea or dehydration, see:
women should always consult their doctors if they think they may
have food poisoning, because the infection can be passed on to the
Toxoplasmosis and listeriosis can also harm your baby. If you are diagnosed with either of these
conditions during pregnancy, you will be treated with antibiotics. To learn more, see Toxoplasmosis During Pregnancy.
You can prevent most cases of
food poisoning by being careful when you prepare and
store food. Wash your hands and working surfaces while preparing food, cook
foods to safe temperatures, and refrigerate foods promptly. Be especially
careful when you cook or heat perishable foods, such as eggs, meats, poultry,
fish, shellfish, milk, and milk products. Also take extra care if
you are pregnant, have an
impaired immune system, or are preparing foods for
children or older people.
The following steps can help prevent
food poisoning (adapted from the U.S. Centers for Disease Control and
Shop safely. Bag raw meat, poultry, and
fish separately from other food items. Young children can get sick from
touching packaged poultry, so don't allow them to touch or play with packages
of poultry in your grocery cart.
Prepare foods safely. Wash your hands before and after handling food. Wash fruits, vegetables, and cutting boards. Follow procedures for safe home canning to avoid contamination.
Store foods safely. Cook, refrigerate,
or freeze meat, poultry, eggs, fish, and ready-to-eat foods within 2 hours.
Make sure your refrigerator is set at
40°F (4°C) or colder.
Cook foods safely. Use a clean meat thermometer to
make sure that foods are cooked to a safe temperature. Reheat leftovers to
at least 165°F (74°C). Don't
eat undercooked hamburger. And be aware of the risk of food poisoning from raw
fish (including sushi), clams, and oysters.
Serve foods safely.
Keep cooked hot foods hot [140°F (60°C) or above] and cold foods cold [40°F (4°C) or below].
When in doubt, throw it out. If you aren't sure if a food
is safe, don't eat it. Reheating food that is contaminated won't make it
safe. Don't taste suspicious food. It may smell and look fine but still may not
be safe to eat.
Make smart restaurant choices.
Note the general cleanliness of the facility and
staff. If you aren't confident that conditions are sanitary,
Restaurants are inspected by the local health department for
cleanliness and proper kitchen procedures. Find out the inspection scores of
selected restaurants. (They are sometimes posted in the restaurant.)
Find out if food safety training is regularly provided for
Many counties in the United States have extension services
listed in the phone book. These services can answer your questions about safe
home canning and food preparation.
To learn more, see Symptoms for a list of specific organisms.
Most cases of
food poisoning will go away in a few days with rest
and care at home. The following information will help you recover.
the most frequent complication of food poisoning. Older persons and children
should take special precautions to prevent it.
To prevent dehydration, take
frequent sips of a
rehydration drink (such as Pedialyte). Try to drink a cup of water or rehydration drink for each large,
loose stool you have. Sports drinks, soda pop, and fruit juices contain too
much sugar and not enough of the important
electrolytes that are lost during diarrhea, so they shouldn't be used to rehydrate. You can
make your own rehydration drink.
Try to stay with your normal
diet as much as possible. Eating your usual diet will help you to get enough
For children who are breast-feeding or bottle-feeding,
continue the regular breast milk or formula feeding as much as possible. You
may have to feed more often to replace lost fluids. Give an
oral rehydration solution (ORS), such as Pedialyte, between feedings only if
you see signs of dehydration.
For older children, give ½ cup
[4 fl oz (118 mL)] to 1 cup
[8 fl oz (237 mL)] of water,
milk, or a rehydration drink each hour, and try to keep feeding your child his
or her usual diet. Foods to try include potatoes, chicken breast without the
skin, cereal, yogurt, and fresh fruits and vegetables. Try to avoid foods that
have a lot of fat or sugar. Supplement feedings with small sips or spoonfuls of
a rehydration drink or clear liquid every few minutes.
information on treating diarrhea or dehydration, see:
Medicines aren't used routinely in
food poisoning. Medicines that stop diarrhea
(antidiarrheals) can help with your symptoms. These medicines (such as Imodium) shouldn't be used if you have a fever or bloody diarrhea, because they can
actually make you sicker. Don't give antidiarrheals to children.
Types of food poisoning that may be treated with medicines
Botulism, which usually requires the
botulism antitoxin and close medical
Listeriosis, which in pregnant women is treated with
antibiotics to prevent infection of the
fetus or newborn. Babies with listeriosis may also
Shigellosis, which may be treated with antibiotics.
But some types of Shigella bacteria aren't killed by
antibiotics. This is called
resistance. Because using antibiotics can make these
bacteria even more resistant, mild cases of shigellosis aren't usually treated
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Primary Medical Reviewer
E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer
W. David Colby IV, MSc, MD, FRCPC - Infectious Disease
How this information was developed to help you make better health decisions.