Food Poisoning or Stomach Bug? Here’s How to Tell the Difference

If your stomach suddenly turns against you, the culprit could be what you just ate or something you picked up from someone else. While food poisoning and stomach bugs share many of the same symptoms, like vomiting, diarrhea, and stomach cramps, the causes and timelines can differ in important ways. Knowing which one you’re facing can help you treat it effectively and prevent it from spreading.

We asked Elena Ivanina, DO, MPH, board-certified integrative gastroenterologist and founder of the Center for Integrative Gut Health, to help break down the signs, symptoms, and recovery tips for both stomach woes.

What Causes Food Poisoning?

Food poisoning happens when you consume contaminated food or drinks often due to improper handling, cooking, or storage. Bacteria like Salmonella, E. coli, and Listeria are frequent offenders, but viruses and parasites can also be involved.

Common foodborne sources include:

• Undercooked meat, eggs, or shellfish

• Raw or unwashed produce

• Soft cheeses and deli meats

• Foods left out too long or not refrigerated properly

Symptoms usually include:

• Nausea and vomiting

• Diarrhea

• Stomach cramps

• Fever and headache

• Fatigue

What Is a Stomach Bug?

A stomach bug, or viral gastroenteritis, is usually caused by viruses like norovirus, which spreads through contaminated food, water, or contact with infected people or surfaces. Norovirus alone infects about 21 million Americans each year, according to the CDC.

Despite being nicknamed the “stomach flu,” it has nothing to do with influenza. Instead, it targets your gastrointestinal tract and is highly contagious.

Symptoms can include:

• Vomiting and diarrhea

• Abdominal cramping

• Low-grade fever

• Body aches, fatigue, and chills

Food Poisoning vs. Stomach Bug: How to Tell

Both can leave you clutching the toilet, but there are a few clues to help you figure out which is to blame:

• Timing of symptoms:
  Food poisoning usually hits fast within a few hours of eating contaminated food. Stomach bugs typically show up 24–48 hours after exposure.

• Duration:
  Food poisoning often lasts less than 24 hours, though some infections can linger. Stomach bugs may last several days to a week, depending on your immune system.

• Contagion risk:
  Food poisoning isn’t usually contagious unless someone comes into direct contact with your bodily fluids. Stomach bugs, especially norovirus, spread easily and quickly so if you’re sick, isolate yourself for at least 48 hours after symptoms stop.

How to Treat Either Infection

For both stomach bugs and food poisoning, the best treatment is usually supportive care:

• Rest: Sleep helps your immune system fight off infections.

• Hydrate: Sip water, electrolyte drinks, or broth to replace fluids lost through vomiting and diarrhea.

• Eat bland foods: Once you’re ready, try easy-to-digest options like bananas, rice, toast, and chicken.

• Avoid irritants: Steer clear of spicy, fatty, or dairy-heavy foods, and skip alcohol and caffeine until you’re fully recovered.

When to Call a Doctor

In most cases, symptoms clear up on their own but some situations call for medical attention:

• Diarrhea or vomiting lasting more than 48 hours

• Signs of dehydration: dry mouth, dizziness, dark urine, or not urinating

• High fever over 101.3°F that doesn’t break

• Severe abdominal pain

• Blood in stool or vomit

If needed, your doctor may order a stool test to identify the specific bacteria or virus, which can guide treatment especially for vulnerable populations like young children, older adults, pregnant people, and those with weakened immune systems.

How to Prevent Food Poisoning and Stomach Bugs

You can’t eliminate all risk, but smart hygiene practices go a long way in reducing your chances of getting sick:

• Wash hands after using the bathroom and before eating or prepping food

• Avoid preparing food while symptomatic and wait 48 hours after symptoms stop

• Wash fruits and veggies thoroughly

• Keep refrigerators at or below 40°F, and freezers at 0°F

• Cook meat, seafood, and eggs to safe internal temperatures

• Clean kitchen surfaces, knives, and cutting boards after handling raw foods

Final Thoughts

Whether your symptoms are from bad food or a contagious bug, the approach is similar rest, hydrate, and be kind to your body as it recovers. If you’re unsure which you have, pay attention to the timing of symptoms and whether others around you are also feeling sick.

And remember stomach illnesses aren’t just unpleasant. For vulnerable individuals, they can be dangerous. When in doubt, reach out to a medical provider for help.

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