First aid · · 8 min read

Food poisoning: symptoms, rehydration and when to get help

Most stomach infections clear up on their own within days, and the main job at home is not to kill a germ but to prevent dehydration. Dehydration, more than the infection itself, is what usually sends people to the hospital. This article gives a simple plan for the first day, explains how to drink and eat, which medicines can help or harm, and which signs mean it is time to see a doctor.

Illustration of a glass of water, a packet of oral rehydration salts and a bowl of rice

In short

  • The goal is to replace fluid and salts, not to stop diarrhea at any cost.
  • Drink small amounts often, especially if you are vomiting.
  • Oral rehydration solution replaces losses better than plain water.
  • You do not need to fast; eat as soon as you feel able.
  • Blood in the stool, high fever or little urine are reasons to see a doctor.

What food poisoning is

Food poisoning is illness from germs in food or drink. The most common symptoms are diarrhea, stomach pain or cramps, nausea, vomiting and fever. They vary by germ, can range from mild to serious, and may start within hours or take several days. Most people with foodborne illness get better on their own, and vomiting usually stops within a day or two while diarrhea usually stops within 5 to 7 days.

Anyone can get it, but it is more likely to make some groups very sick: people 65 and older, children under 5, people with weakened immune systems and pregnant women.

The first 24 hours: step by step

  1. Check for red flagsRead the red flag section below. If any apply, get medical help instead of starting home care.
  2. Start with sipsIf you feel sick, take small sips often. A big gulp can bring on more vomiting.
  3. Add saltsUse oral rehydration solution, which a pharmacist can recommend. It is clean water with the right balance of sugar and salt, and it replaces the water and electrolytes you lose.
  4. RestStay home, avoid hard work and do not drive while weak or dizzy.
  5. Eat when you canOnce you feel able, start with simple foods in small portions.
  6. Watch your urineDark urine or passing much less than usual is a sign of dehydration.

How to replace fluids

Dehydration is the most serious threat from diarrhea, because fluid and electrolytes are lost through stool and vomit and need to be replaced. Oral rehydration solution is the main treatment for it. Prepare it exactly as the package directs, because the balance of salts and sugar is what lets the gut absorb water.

Avoid fruit juice and fizzy drinks, which can make diarrhea worse. Alcohol is best left alone too. Do not dilute infant formula, and babies should keep breast or bottle feeding, in smaller, more frequent feeds if they are being sick.

What you can eat

  • Eat when you feel able; WHO advises continuing nutrient-rich food during diarrhea.
  • Start with simple foods in small portions, such as rice, potatoes, bread, bananas or soup.
  • Avoid fatty or spicy foods while you recover.
  • Do not force food when you are nauseated; fluids come first.

Medicines: be careful

  • Anti-diarrheal medicines: a pharmacist may suggest one for adults with simple watery diarrhea. They are not suitable for children under 12, and they are not for anyone with blood in the stool or a high fever unless a doctor says so.
  • Pain and fever relief: ask a pharmacist what suits you.
  • Antibiotics: most food poisoning does not need them. A doctor may prescribe one if a specific cause is identified.
  • Your regular medicines: if you have severe vomiting or diarrhea, ask your provider whether to adjust water pills, blood pressure medicines or diabetes drugs for a while.

Signs of dehydration

  • Not urinating much, or dark urine.
  • Dry mouth and throat.
  • Dizziness when you stand up.
  • In children under 5, fewer wet diapers.

The very young, older adults, pregnant people and those with long-term illnesses are most vulnerable. For them, contact a provider sooner rather than waiting for dehydration to become obvious.

Prevention in the kitchen and on the road

  • Clean: wash hands, surfaces and utensils often, and rinse fresh produce under running water.
  • Separate: keep raw meat, poultry, seafood and eggs apart from ready-to-eat foods, with separate cutting boards.
  • Cook: use a food thermometer, since color and texture are not reliable. CDC lists 165°F for poultry and leftovers and 160°F for ground beef.
  • Chill: refrigerate promptly and keep the refrigerator at 40°F or below.
  • Do not leave perishable food out more than 2 hours, or 1 hour when it is above 90°F.
  • Stay off school or work until you have had no vomiting or diarrhea for at least 2 days, and wash your hands often.

Red flags and when to see a doctor

Red flags: call 911 or go to an emergency department for confusion, fainting, blood in your vomit, severe difficulty breathing, a sudden severe headache or belly pain, or when you cannot keep liquids down and are getting worse. Difficulty swallowing, muscle weakness, double or blurred vision, drooping eyelids or slurred speech can signal botulism, which can follow improperly canned or fermented food, and needs emergency care.

See a doctor for bloody diarrhea, diarrhea lasting more than 3 days, a fever over 102°F, vomiting so often you cannot keep liquids down, or signs of dehydration. Contact your provider early if you are pregnant, have a weakened immune system, or are caring for a baby.

Questions for your provider

  • Do I need a stool test or other tests?
  • Is an anti-diarrheal medicine safe for me?
  • Should I adjust any of my regular medicines for now?
  • How much fluid should I aim for each day?
  • When will I stop being contagious to my household?
  • Which symptoms mean I should come back right away?

Questions and answers

How long does food poisoning usually last?

Vomiting typically stops within a day or two, and diarrhea within 5 to 7 days. If diarrhea lasts more than 3 days, or the illness is getting worse, see a clinician.

Is plain water enough?

Water replaces volume but not the salts you lose in stool and vomit. Oral rehydration solution is designed to replace both, which matters most when losses are heavy.

Should I stay away from other people?

Yes. Stay off school or work until you have had no sickness or diarrhea for at least 2 days, and avoid swimming pools until at least 48 hours after symptoms stop.

Do I need antibiotics?

Usually not. Most people with foodborne illness recover without them, and a doctor may prescribe one only when a specific cause is found.

Why can food left on the counter make me sick?

Germs multiply at room temperature, which is why CDC advises discarding perishable food left out for more than 2 hours, or 1 hour in hot weather.

Sources

  1. CDC — Food Poisoning Symptoms
  2. CDC — Food Safety Basics
  3. CDC — Four Steps to Food Safety
  4. WHO — Diarrhoeal disease
  5. NHS — Diarrhoea and vomiting
  6. MedlinePlus — Foodborne Illness

Sources checked on 29 October 2026.

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