Food poisoning is illness from food or water contaminated with bacteria, viruses, parasites, or their toxins, causing diarrhea, stomach cramps, nausea, vomiting, and sometimes fever. It almost always gets better on its own — the NHS notes the symptoms usually get better within a week — so there is no medicine that "cures" it. The single most important thing is replacing lost fluids to prevent dehydration; over-the-counter medicines can ease symptoms but are optional and carry real cautions, and antibiotics are usually not needed and not appropriate to self-start.
Available without a prescription — follow each label.
oral rehydration salts Pedialyte, DripDrop (or pharmacy ORS sachets) Oral rehydration solution (ORS) | Not a drug, but the cornerstone of treatment: a balanced mix of water, salts, and sugar that replaces fluids and electrolytes lost to vomiting and diarrhea better than water alone. Best for anyone at risk of dehydration, especially young children and older adults. Sip slowly. Avoid fruit juice and fizzy drinks, which can make diarrhea worse. |
loperamide Imodium Antidiarrheal (slows gut motility) | Can slow diarrhea for a few hours in adults to help you cope. Optional symptom relief only. Do NOT use it — and talk to a doctor first — if you have a fever, bloody diarrhea, or severe diarrhea, because slowing the gut can trap the infection and make things worse. Not suitable for children under 12; follow the Drug Facts label. |
bismuth subsalicylate Pepto-Bismol, Kaopectate Antidiarrheal / antacid (bismuth) | May ease nausea, upset stomach, and mild diarrhea. Same caution as loperamide: avoid with fever or bloody stools without talking to a clinician. Contains a salicylate, so do not give to children or teenagers (Reye's syndrome risk) and avoid if you can't take aspirin; it can harmlessly darken the tongue and stool. |
Tylenol Analgesic / antipyretic | The NHS suggests a pain reliever such as paracetamol (acetaminophen in the US) if you are in discomfort with fever or aches. Generally gentler on an upset stomach than anti-inflammatory painkillers. Follow the Drug Facts label and check the leaflet before giving to a child. |
A doctor may prescribe these — not for self-treatment.
antibiotics (e.g. azithromycin, ciprofloxacin) Antibiotics | Most food poisoning is not treated with antibiotics — MedlinePlus states that for the most common causes a provider will NOT prescribe them. A doctor may prescribe one only for specific confirmed bacterial or parasitic infections, for high-risk patients, or for severe illness, based on stool testing and diagnosis. The wrong antibiotic can be unhelpful or harmful for some infections, so never self-start a leftover antibiotic for diarrhea. |
prescription antiemetics (e.g. ondansetron) Antiemetic (anti-nausea) | For severe or persistent vomiting, a clinician may prescribe an anti-nausea medicine to help you keep fluids down. This is a doctor's decision after evaluation, not something to self-start; persistent vomiting that prevents you keeping liquids down is itself a reason to seek care. |
IV fluids (clinician-supervised rehydration) Supportive rehydration | The main 'treatment' for serious cases is rehydration. MedlinePlus notes that if dehydration is severe or you can't keep fluids down, a clinician may give fluids through a vein (IV) — most often needed in young children and older or frail adults. This requires medical assessment. |
Hydration first, medicine second. Rest and sip fluids steadily — water, diluted squash, or an oral rehydration solution (ORS) like Pedialyte; ORS is especially worth it for young children and older adults because it replaces salts as well as water. Take small sips if you feel sick, keep going even after vomiting, and avoid fruit juice and fizzy drinks, which can worsen diarrhea. Eat when you feel able, favoring bland foods and avoiding fatty or spicy ones. For fever or aches, acetaminophen (paracetamol) is a reasonable choice. Antidiarrheal medicines such as loperamide or bismuth subsalicylate are optional comfort measures for adults — they can reduce trips to the bathroom but do not cure the illness, and there is limited evidence that any OTC medicine shortens food poisoning. Critically, do not use antidiarrheals if you have a fever, bloody diarrhea, or severe diarrhea, and do not give them to children — MedlinePlus advises slowing the gut in those situations can make the infection worse. Skip antibiotics unless a doctor diagnoses a specific infection that needs them; for the most common causes they are not prescribed.
Call your doctor or seek urgent care if you have: bloody diarrhea or blood/pus in the stool; a high fever (over about 102°F / 39°C, or over 100.4°F / 38°C in a child); diarrhea lasting more than 3 days (sooner in infants); vomiting so often you cannot keep any liquids down; or signs of dehydration — peeing little or not at all, very dark urine, a dry mouth and throat, sunken eyes, dizziness when standing, or (in babies) few wet diapers or no tears. Be extra cautious and seek care earlier if you are pregnant, over 65, an infant or young child, or have a weakened immune system or chronic illness. Get emergency care (call 911) for severe or constant stomach pain, vomiting blood, a stiff neck with severe headache and light sensitivity, or double vision, muscle weakness, drooping eyelids, slurred speech, or trouble swallowing or breathing (possible botulism), or suspected poisoning from mushrooms or seafood. Also contact a clinician if symptoms haven't improved after about a week.
General reference, not medical advice, and not a substitute for your doctor or pharmacist. The right choice depends on your symptoms, health conditions, age, and other medicines — always read each label and confirm before taking anything.