Diagnosis

A healthcare professional bases a diagnosis of food poisoning, a type of foodborne illness, on a physical exam and a review of things that may be causing vomiting, loose stool or other symptoms. Your healthcare professional may ask about:

  • Your symptoms.
  • Food or drinks you've had recently.
  • Symptoms in people who ate with you.
  • Recent changes in the medicines you take.
  • Recent travel.

Your healthcare professional does an exam to rule out other causes of illness and check for signs of fluid loss, called dehydration.

You may have tests that include:

  • Stool sample tests to find the bacteria, viruses, parasites or toxins.
  • Blood tests to find a cause of illness, rule out other conditions or find complications.

When a person or a family gets food poisoning, it's hard to know what food was tainted. It can take hours or days to get sick. During that time, the person or family may have had other meals. This makes it hard to find what food caused the illness.

In a large outbreak, public health officials may be able to find what food all those affected shared.

Treatment

Treatment for food poisoning, a type of foodborne illness, depends on how bad your symptoms are and what caused the illness. Most often, you don't need medicine.

Treatment may include the following:

  • Fluid replacement. Fluids and electrolytes keep the balance of fluids in the body. Electrolytes include minerals such as sodium, potassium and calcium. After vomiting or having loose stools, replace fluids to prevent dehydration. Serious dehydration may result in a hospital stay to get fluids and electrolytes through a vein, called IV fluids.
  • Antibiotics. A healthcare professional may prescribe an antibiotic for illness caused by bacteria. Antibiotics are mainly for people with serious illness or with a higher risk of complications.
  • Antiparasitics. For parasitic infections, healthcare professionals most often prescribe medicines that target parasites. These medicines are called antiparasitics.
  • Probiotics. A healthcare professional may suggest probiotics. These are treatments that replace healthy bacteria in the belly.

Medicines for loose stools or upset stomach

Adults who have loose stools that aren't bloody and who have no fever may take loperamide (Imodium A-D) to treat diarrhea. They also may take bismuth subsalicylate (Pepto-Bismol, Kaopectate, others) to treat an upset stomach. These are medicines you can get without a prescription. They are not for children.

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Lifestyle and home remedies

For most people, symptoms of food poisoning, a type of foodborne illness, improve without treatment within 48 hours.

To help relieve symptoms and prevent fluid loss, called dehydration, focus on replacing lost fluids. Water, broth or drinks that contain minerals called rehydration solutions are options for helping to replace fluids. Talk with your healthcare professional before giving rehydration fluids to infants.

As you start to feel better, the suggestions on what to eat vary. Some people stop eating until their stomach feels better and they don’t feel like vomiting. Low fat foods like crackers, noodles, bananas, rice, boiled vegetables, soup or oats can be sampled to see if they stay down. While yogurt might be fine, other dairy products might cause an upset stomach.

Preparing for your appointment

Start by seeing your main healthcare professional for food poisoning, a type of foodborne illness. Sometimes, you may need to see a specialist in infectious diseases.

Be ready to answer the following questions.

  • When did your symptoms begin?
  • Do you always have symptoms, or do they come and go?
  • Have you had bloody stools?
  • Have you had black or tarry stools?
  • Have you had a fever?
  • What have you eaten lately?
  • Did anyone else who ate the same food have symptoms?
  • Have you traveled lately? Where?
  • What medicines, dietary supplements or herbal remedies do you take?
  • Had you taken antibiotics in the days or weeks before your symptoms started?
  • Have you recently changed medicines?
Aug. 16, 2025
  1. Food safety. U.S. Centers for Disease Control and Prevention. https://www.cdc.gov/food-safety/about/index.html. Accessed Feb. 25, 2025.
  2. Definition & facts of food poisoning. National Institute of Diabetes and Digestive and Kidney Diseases. https://www.niddk.nih.gov/health-information/digestive-diseases/food-poisoning/definition-facts. Accessed Feb. 25, 2025.
  3. LaRocque R, et al. Causes of acute infectious diarrhea and other foodborne illnesses in resource-abundant settings. https://www.uptodate.com/contents/search. Accessed Feb. 25, 2025.
  4. Kellerman RD, et al. Foodborne illnesses. In: Conn's Current Therapy 2025. Elsevier; 2025. https://www.clinicalkey.com. Accessed Feb. 26, 2025.
  5. Bennett JE, et al. Foodborne disease. In: Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Elsevier; 2020. https://www.clinicalkey.com. Accessed Feb. 25, 2025.
  6. Molds on food: Are they dangerous? Food Safety and Inspection Service. U.S. Department of Agriculture. https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/molds-food-are-they-dangerous. Accessed Feb. 26, 2025.
  7. LaRocque R, et al. Approach to the adult with acute diarrhea in resource abundant settings. https://www.uptodate.com/contents/search. Accessed March 27, 2025.

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