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Food Poisoning (Foodborne Illness)

Food poisoning is illness from eating food that is contaminated. The food may have harmful bacteria or viruses. Or it may have parasites or toxins (poisons). Food poisoning happens when food isn’t cooked, handled, or stored safely. 

You may have nausea, vomiting, diarrhea, and stomach cramps. When your symptoms start depends on the type of infection. For example:


  • Symptoms from a toxin made by bacteria usually happen in 1 to 6 hours. Toxins may be from Staphylococcus aureus or Bacillus cereus.

  • Symptoms from botulism toxin often start in 12 to 36 hours. The toxin is from bacteria called Clostridium botulinum. The toxin may be found in foods canned or bottled at home. It attacks the nervous system. You may have a headache, blurred vision, and muscle weakness.

  • Symptoms from just the bacteria often take longer to happen. This could be from 6 hours to several days or weeks. The amount of time depends on the type of bacteria.

  • Symptoms from hepatitis A virus or Listeria bacteria may not happen until 50 days after you eat the food.


If you have a mild food poisoning

  • Rest and drink plenty of liquids.

  • Don't eat solid foods until you feel better.

  • Don’t take medicines for diarrhea unless your doctor tells you to.

When to go to the emergency room (ER)

Call 911 or go the ER if you have any of these:

  • Symptoms of botulism. It can be fatal. Don't delay in getting help.

  • Severe symptoms, such as bloody vomit or diarrhea

  • Symptoms for more than 12 hours

  • Heart that is racing, pounding, or skipping beats

  • Trouble breathing

  • Elderly age

  • Stomach or colon problems

  • Chronic liver disease

  • Hemochromatosis

  • A weak immune system

  • Signs of dehydration such as extreme thirst, dizziness, not much urine, weakness, or lightheadedness

What to expect in the ER

A healthcare provider will ask you about your symptoms. He or she will give you a physical exam. Your blood pressure, pulse, breathing rate, and temperature will be checked. A sample of your stool may be tested for bacteria. There are many types of foodborne diseases, so treatment will depend on your symptoms. You’ll likely be given fluids through a vein in your arm (IV). This helps replace water and minerals lost with vomiting and diarrhea. You may need to stay in the hospital if your symptoms are very severe.

Online Medical Reviewer: Cynthia Godsey
Online Medical Reviewer: Diane Horowitz MD
Online Medical Reviewer: Kenny Turley PA-C
Date Last Reviewed: 4/1/2020
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