Food poisoning is illness from eating food that is contaminated. The food may have harmful bacteria, parasites, or viruses. Or it may have toxins (poisons). Food poisoning mainly 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:
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Symptoms from a toxin made by bacteria usually happen in 1 to 6 hours. Toxins may be from Staphylococcus aureus or Bacillus cereus.
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Symptoms from botulism toxin often start in 12 to 72 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.
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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.
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Symptoms from hepatitis A virus or Listeria bacteria may not happen until 6 to 7 weeks or more after you eat the food.
If you have a mild food poisoning
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Rest and drink plenty of liquids.
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Don't eat solid foods until you feel better.
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Don’t take medicines for diarrhea unless your doctor tells you to.
When to go to the emergency room (ER)
Call
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Symptoms of botulism. These include vomiting, diarrhea, blurred vision, difficulty swallowing, and muscle weakness. These symptoms can cause respiratory failure and death. Don't delay in getting help.
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Severe symptoms, such as bloody vomit or diarrhea
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Symptoms for more than 12 hours
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Heart that is racing, pounding, or skipping beats
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Trouble breathing
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Elderly age
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Stomach or colon problems
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Chronic liver disease
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Extra iron buildup in the blood (hemochromatosis)
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A weak immune system
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Signs of dehydration, such as extreme thirst, dizziness, not much urine, weakness, or lightheadedness
What to expect in the ER
A doctor will ask you about your symptoms. They 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. Treatment will depend on your symptoms and which bacteria, virus, parasite, or toxin you have been exposed to. 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: Daphne Pierce-Smith RN MSN
Online Medical Reviewer: Raymond Turley Jr PA-C
Online Medical Reviewer: Shaziya Allarakha MD
Date Last Reviewed: 04/01/2025
© 2000-2025 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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