Best medicine for diarrhea
A curated shortlist, over-the-counter and prescription. Standing in the pharmacy aisle instead? The over-the-counter shelf for diarrhea, product by product →
Most short-term (acute) diarrhea is caused by a viral or food-borne bug and clears on its own within about 5 to 7 days, so treatment is mainly self-care: replacing lost fluids and salts to prevent dehydration, with optional over-the-counter medicines for symptom relief. Antibiotics or other prescription drugs are reserved for specific causes (such as a confirmed bacterial infection) and need a doctor.
What diarrhea is, how it is treated, and every drug we rate for it →
For options we rate, we show our independent FDA recall-safety rating(0–100) — a signal GoodRx and Drugs.com don’t provide. Higher is safer.
Over-the-counter options
Available without a prescription — follow each label.
oral rehydration salts Pedialyte oral rehydration solution (electrolytes) | The single most important treatment: replaces the water, salt, and sugar lost in loose stools to prevent dehydration. Pharmacists recommend mixing the powder sachets with water, or using a ready-made electrolyte drink, especially for the very young, older adults, and anyone peeing less or with dark urine. |
Imodium antimotility (antidiarrheal) agent | Slows the gut so stools become firmer and less frequent; best for short-term relief of uncomplicated, watery diarrhea (e.g. to get through travel). Do NOT use it if you have a fever or bloody/black stools, and stop and call a doctor if your diarrhea lasts longer than 48 hours. Not recommended for children under 12 unless a doctor advises (the OTC product should never be given to a child under 2). Never exceed the label dose — taking more than the recommended amount can cause serious, even life-threatening heart-rhythm problems. |
bismuth subsalicylate Pepto-Bismol antidiarrheal / antisecretory (salicylate) | Eases diarrhea plus upset stomach, nausea, and indigestion by reducing fluid in the bowel and calming inflammation; also used to help prevent travelers' diarrhea. Can harmlessly turn the tongue or stool black. Avoid if you are allergic to aspirin; do not give to children or teens recovering from flu or chickenpox (Reye's syndrome risk). |
Prescription options
A doctor may prescribe these — not for self-treatment.
Lomotil opioid antimotility agent Our rating 58/100 | A doctor may prescribe this to slow severe or persistent watery diarrhea when an over-the-counter antimotility drug isn't enough. It is a controlled medicine (diphenoxylate is a weak opioid) and is not used when stools are bloody or a fever is present. |
Zithromax macrolide antibiotic Our rating 70/100 | A doctor may prescribe a short antibiotic course for a confirmed or likely bacterial cause — for example bloody, febrile, or travelers' diarrhea (dysentery). Azithromycin is often preferred. Antibiotics are not appropriate for ordinary viral diarrhea and must be chosen by a clinician. |
Cipro fluoroquinolone antibiotic Our rating 56/100 | A doctor may prescribe a fluoroquinolone for bacterial travelers' diarrhea, though resistance is now common in parts of Asia. Reserved for clinician-diagnosed bacterial infection — never self-started. |
Xifaxan non-absorbed (gut-selective) antibiotic | A doctor may prescribe rifaximin for non-bloody, non-febrile bacterial travelers' diarrhea, or for certain chronic conditions. It is not used when diarrhea is bloody or accompanied by fever. |
Just want the drugstore answer?
If you are standing in the pharmacy aisle rather than deciding whether to see a clinician, our deeper page on what actually works over the counter for diarrhea takes each product one at a time: how strong the evidence is, the limits printed on its own label, and when an OTC product is the wrong answer entirely.
How to choose
For most adults, start with self-care: rest, sip plenty of fluids, and use oral rehydration salts if you notice any signs of dehydration — this matters more than any pill. Eat small, plain meals when you can and skip greasy, very spicy, or high-fiber foods, caffeine, and alcohol for a day or two. If you simply need to reduce trips to the bathroom for non-bloody, fever-free diarrhea, loperamide works fastest, while bismuth subsalicylate is a good choice if you also have nausea or an upset stomach. Crucially, do NOT use any antidiarrheal medicine if you have a high fever or blood in your stool — these point to an infection that can be made worse by slowing the gut, and need a doctor. Don't give loperamide to young children, and treat infants, older adults, and people with weakened immune systems with extra caution and a lower threshold for medical advice.
When should I see a doctor?
See a doctor (or seek urgent care) if you have: blood or pus in your stool, or black, tarry stools; a fever above about 102°F (39°C), or 101°F with diarrhea; severe stomach or rectal pain; or signs of dehydration such as very dark urine, peeing much less than usual, dry mouth, sunken eyes, dizziness, or confusion. Also get medical advice if diarrhea lasts more than 5–7 days in an adult (sooner if it is getting worse), if vomiting prevents you from keeping fluids down, or if it follows recent travel abroad or a course of antibiotics. For infants and young children, contact a provider if diarrhea does not improve within about 2 days or there are any signs of dehydration (no wet diapers, no tears, listlessness). Call emergency services for vomiting blood or material like coffee grounds, a stiff neck with light sensitivity, sudden severe headache or abdominal pain, trouble breathing, or someone who is very drowsy or unresponsive.
Before you combine anything
Sources
- Diarrhoea and vomiting — NHS ↗
- Loperamide: a medicine used to treat diarrhoea — NHS ↗
- When you have diarrhea — MedlinePlus Medical Encyclopedia ↗
- Diarrhea — MedlinePlus Medical Encyclopedia ↗
- Loperamide — MedlinePlus Drug Information ↗
- Pepto-Bismol (bismuth subsalicylate) Drug Facts label — DailyMed (NIH) ↗
- Travelers' Diarrhea — CDC Yellow Book ↗
- Diphenoxylate — MedlinePlus Drug Information ↗
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.