Symptoms and Signs of Food Poisoning vs. Stomach Flu

Medical Author:
Medically Reviewed on 11/24/2021

Doctor's Notes on Food Poisoning vs. Stomach Bug: Comparison of Differences

Food poisoning is an illness caused by eating or drinking contaminated food or water. The contaminants can be viruses, bacteria, toxins, parasites, or chemicals. Stomach flu (gastroenteritis) is a general term used for various inflammatory problems in the digestive tract, some of which include food poisoning causes. The most common food poisoning symptoms and signs are abdominal cramps, nausea, vomiting, and diarrhea. More severe food poisoning symptoms may include

  • blood in the stool or vomit,
  • dehydration,
  • high fevers,
  • diarrhea the last for 3 days,
  • headaches,
  • weakness,
  • blurry vision,
  • bloating,
  • renal problems,
  • numbness tingling or burning sensation to the extremities,
  • seizures, and
  • death.

Signs and symptoms of gastroenteritis are less severe than those for food poisoning and include

  • low-grade fevers,
  • nausea without vomiting,
  • mild to moderate diarrhea, and
  • crampy abdominal bloating.

However, more serious symptoms and signs can occur such as blood in vomitus or stools, vomiting more than 48 hours, fever high than 101 F, swollen abdomen with increasingly severe abdominal pain, and dehydration. Most causes of food poisoning last from a few hours to a few days while gastroenteritis last from 1 to 2 days to months.

Viruses are the most frequent cause of food poisoning in the U.S. The next highest causes are bacteria while other causes include chemicals, parasites, and toxins. Viruses cause about 70% of gastroenteritis problems, and bacterial infections cause most of the rest.

How Do the Treatments Differ for Food Poisoning and Gastroenteritis?

Treatments for food poisoning and gastroenteritis have almost the same treatments. In general, the treatments for both include the following:

  • Drink plenty of fluids.
  • Some fluids should contain electrolytes (sodium, potassium, calcium).
  • Use antibiotics or antiparasitic drugs (if cause is viral, do not treat with antibiotics) appropriately.
  • If symptoms are severe, IV fluids and possible IV drugs in a hospital may be necessary.

The main difference is that food poisoning can have toxic ingestions that when stopped may resolve quickly where gastroenteritis may take days to months to resolve. However, some patients may not have the predicted resolutions, so an accurate diagnosis of the cause of symptoms and is important for treatment.

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Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.