Definition & Facts of Food Poisoning

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What is food poisoning?

Food poisoning, also called foodborne illness, is an infection or irritation of your digestive tract that spreads through food or drinks. Viruses, bacteria, and parasites cause most food poisoning. Harmful chemicals may also cause food poisoning.

Food poisoning is most often acute, meaning it happens suddenly and lasts a short time. Most cases of food poisoning last less than a week, and most people get better on their own without treatment. In some cases, food poisoning can last longer or lead to serious complications.1

How common is food poisoning?

Each year, about 48 million people in the United States have food poisoning. Food poisoning causes about 3,000 deaths in the United States each year.2

Who is more likely to get food poisoning?

Although anyone can get food poisoning, some people are more likely to get food poisoning than others, including

  • infants and children
  • pregnant women and their fetuses
  • older adults
  • people with weak immune systems

People in these groups are also more likely to have severe symptoms or complications of food poisoning. Food safety is especially important for people in these groups. Learn more about food safety for people who are more likely to get food poisoning and have complications.

A sick boy sitting on his mother’s lap.
Some people are more likely to get food poisoning than others, including infants and children.

What are the complications of food poisoning?

In some cases, food poisoning can lead to dehydration, hemolytic uremic syndrome, or other complications. However, serious complications are uncommon. In most cases, food poisoning lasts only a short time, and most people recover without developing complications.


Dehydration is the most common complication of food poisoning. When food poisoning causes you to vomit or have diarrhea, your body loses fluids and electrolytes. If you don’t replace those fluids and electrolytes, you may become dehydrated. When you are dehydrated, your body doesn’t have enough fluid and electrolytes to work properly. See a list of symptoms of dehydration.

Dehydration is especially dangerous in children, older adults, and people with weakened immune systems. If you are dehydrated, see a doctor right away to prevent serious health problems. Without treatment, dehydration can lead to problems such as organ damage, shock, coma, or even death.

Hemolytic uremic syndrome

Hemolytic uremic syndrome (HUS) is a kidney condition that happens when red blood cells are destroyed and block the kidneys’ filtering system. If your kidneys stop working, you have acute kidney injury—the sudden and temporary loss of kidney function.

The most common cause of HUS is infection with a strain of Escherichia coli (E. coli) bacterium called E. coli O157:H7, although other bacteria and viruses may also cause this condition. HUS is most common in children younger than age 5. 3, 4

See a list of symptoms of HUS.

Other complications

In some cases, food poisoning may lead to serious health problems such as

  • health problems during pregnancy and pregnancy complications. Some types of food poisoning during pregnancy can cause complications, such as dehydration, for the pregnant woman or can affect the fetus. For example, food poisoning by the bacterium Listeria can cause miscarriage or stillbirth.
  • Guillain-Barre syndrome, which may occur after food poisoning caused by bacteria or viruses, most commonly Campylobacter jejuni.
  • irritable bowel syndrome, which may occur after food poisoning caused by various bacteria, viruses, or parasites.
  • problems breathing due to botulism—a rare type of food poisoning caused by Clostridium botulinum and sometimes by Clostridium butyricum or Clostridium baratii—and some forms of fish and shellfish poisoning, which affect the nervous system and may paralyze the muscles that control your breathing.
  • reactive arthritis, which may occur after food poisoning by certain bacteria, viruses, and parasites, including Campylobacter jejuni and Salmonella.


Last Reviewed June 2019
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This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. NIDDK translates and disseminates research findings to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by NIDDK is carefully reviewed by NIDDK scientists and other experts.