Overview
Stomach bugs (viral gastroenteritis) and food poisoning (foodborne illness) both cause sudden gastrointestinal symptoms like vomiting and diarrhea, but differ in cause and spread. A stomach bug is typically caused by viruses like norovirus or rotavirus and spreads easily from person to person. Food poisoning is usually caused by bacteria, viruses, or parasites from contaminated food or water. While both conditions can feel similar, food poisoning often has a quicker onset after eating contaminated food, whereas stomach bugs may take longer to develop and are more contagious.
Disease Summaries
Stomach Bug: A viral infection of the stomach and intestines is commonly referred to as the "stomach flu" or stomach bug. It spreads through contact with infected individuals, contaminated food, water, or surfaces. Practicing good hand hygiene and avoiding the sharing of food and drinks are key to preventing transmission.
Food Poisoning: Food poisoning or foodborne illness is a gastrointestinal illness caused by consuming contaminated food or water, often due to bacteria, viruses, or parasites. Common symptoms include nausea, vomiting, diarrhea, and abdominal pain. It typically results from improper food handling, storage, or preparation. Proper food hygiene, such as cooking food thoroughly and washing hands, can help prevent foodborne illnesses.
Comparing Symptoms
Overlapping Symptoms
- Nausea and vomiting
- Diarrhea
- Stomach cramps
- Fatigue
- Loss of appetite
Stomach Bug Specific Symptoms
- Watery diarrhea lasting 1–3 days
- Mild fever
- Muscle aches
- Headache
- Contagious through direct contact
Food Poisoning Specific Symptoms
- Sudden onset within hours of eating
- Severe abdominal cramping
- Possible fever and chills
- Bloody or persistent diarrhea (in some bacterial cases)
- Symptoms may vary based on the contaminant (e.g., Salmonella, E. coli, Listeria)
Treatment Approaches
Stomach Bug Treatment Approaches
This condition usually improves without treatment. Simple steps include maintaining good hydration, and avoiding dairy products or spicy food. Medicines may be taken to help with vomiting or diarrhea. In severe cases, fluids can be given through the veins for dehydration.
Food Poisoning Treatment Approaches
Treatment depends on the cause, but most cases improve without antibiotics. Staying hydrated is essential, especially if vomiting or diarrhea is severe. Avoid raw or high-fat foods, and gradually reintroduce bland meals. Anti-diarrheal or anti-nausea medications may be used cautiously. If a bacterial infection is confirmed or symptoms are prolonged, antibiotics or medical care may be required. In rare, severe cases, hospitalization and IV fluids are necessary.
Reviewed By:

Kenji Taylor, MD, MSc (Family Medicine, Primary Care)
Dr. Taylor is a Japanese-African American physician who grew up and was educated in the United States but spent a considerable amount of time in Japan as a college student, working professional and now father of three. After graduating from Brown, he worked in finance first before attending medical school at Penn. He then completed a fellowship with the Centers for Disease Control before going on to specialize in Family and Community Medicine at the University of California, San Francisco (UCSF) where he was also a chief resident. After a faculty position at Stanford, he moved with his family to Japan where he continues to see families on a military base outside of Tokyo, teach Japanese residents and serve remotely as a medical director for Roots Community Health Center. He also enjoys editing and writing podcast summaries for Hippo Education.

Aiko Yoshioka, MD (Gastroenterology)
Dr. Yoshioka graduated from the Niigata University School of Medicine. He worked as a gastroenterologist at Saiseikai Niigata Hospital and Niigata University Medical & Dental Hospital before serving as the Deputy Chief of Gastroenterology at Tsubame Rosai Hospital and Nagaoka Red Cross Hospital. Dr. Yoshioka joined Saitama Saiseikai Kawaguchi General Hospital as Chief of Gastroenterology in April 2018.
Content updated on Apr 29, 2025
Following the Medical Content Editorial Policy
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https://www.nejm.org/doi/full/10.1056/NEJM198102123040705Stuempfig ND, Seroy J. Viral Gastroenteritis. [Updated 2023 Jun 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-.
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