For most adults with acute diarrhea, an over-the-counter medication like loperamide (Imodium) or bismuth subsalicylate (Pepto-Bismol) will slow things down while your body recovers. Staying hydrated matters more than any pill, though, and most episodes resolve on their own within a few days. Here’s what works, what to eat, and when the situation calls for something stronger.
Loperamide: The Fastest OTC Option
Loperamide, sold as Imodium, is the most widely used over-the-counter diarrhea medication. It works by slowing down the movement of your intestines, giving them more time to absorb water from stool. The result is fewer, firmer bowel movements.
The standard adult dose is 4 mg (two capsules or tablets) after your first loose bowel movement, then 2 mg after each additional loose stool. Don’t exceed 8 mg in 24 hours for the over-the-counter tablet form, or 16 mg for the capsule form. Most people notice improvement within an hour or two.
Loperamide is best for run-of-the-mill diarrhea from dietary triggers, stress, or a mild stomach bug. You should avoid it if you have a high fever, bloody stools, or suspect a bacterial infection, because slowing your gut in those situations can trap the pathogen inside and make things worse.
Bismuth Subsalicylate: A Gentler Alternative
Bismuth subsalicylate, the active ingredient in Pepto-Bismol and Kaopectate, takes a different approach. It reduces inflammation in the gut lining and has mild antimicrobial properties, which is why it also helps with nausea, heartburn, and upset stomach alongside diarrhea. It’s a good choice when your symptoms include more than just loose stools.
The typical adult dose is two tablets (or two tablespoons of the liquid) every 30 minutes to one hour as needed, up to 16 tablets or 16 tablespoons of regular-strength liquid in 24 hours. It works more gradually than loperamide.
There are important restrictions with this one. Bismuth subsalicylate contains a salicylate, the same class of compound found in aspirin. If you’re allergic to aspirin, have a bleeding disorder, gout, kidney disease, or a stomach ulcer, skip it entirely. It’s also unsafe during breastfeeding and should not be given to children under 12 due to the risk of Reye’s syndrome, a rare but serious condition linked to salicylates in kids with viral illnesses. If you’re already taking aspirin or any other salicylate product, combining them can push you toward an overdose.
Hydration Is the Real Treatment
Diarrhea pulls water and electrolytes out of your body fast. Severe cases, defined as more than 10 bowel movements a day or fluid losses that outpace what you’re drinking, can lead to dehydration quickly. For most people, the biggest risk from a bout of diarrhea isn’t the diarrhea itself but the fluid loss that comes with it.
Water alone helps, but it doesn’t replace lost electrolytes. Oral rehydration solutions (sold as Pedialyte or store-brand equivalents) are the most effective option. Broth, diluted juice, and sports drinks also work in a pinch, though sports drinks tend to be high in sugar, which can sometimes worsen loose stools. Sip steadily rather than gulping large amounts at once.
Signs you’re getting dehydrated include excessive thirst, dry mouth, dark urine, dizziness, and producing little or no urine. In children, watch for no wet diaper in three or more hours, sunken eyes or cheeks, or skin that stays pinched up instead of flattening back down when released.
What to Eat (and What to Skip)
You may have heard of the BRAT diet: bananas, rice, applesauce, and toast. While those foods are gentle on the stomach, most experts no longer recommend restricting yourself to them. The National Institute of Diabetes and Digestive and Kidney Diseases advises that once you feel like eating again, you can return to your normal diet. Children with acute diarrhea should continue their usual age-appropriate meals, and infants should keep getting breast milk or formula.
That said, a few things are worth avoiding while your gut recovers. Greasy, fried, or very spicy foods can irritate an already sensitive digestive tract. Dairy can be harder to digest temporarily because diarrhea sometimes reduces the enzymes that break down lactose. Caffeine and alcohol both speed up gut motility, which is the opposite of what you want. High-sugar foods and drinks, including fruit juice in large quantities, can draw more water into the intestines and worsen symptoms.
When Prescription Medication Is Needed
If diarrhea is chronic, meaning it persists for four weeks or more, over-the-counter options are typically just a bandage. Chronic diarrhea usually has an underlying cause that needs its own treatment. Irritable bowel syndrome with diarrhea (IBS-D) is one of the most common culprits, and there are prescription medications specifically designed for it, including drugs that regulate gut movement and reduce the pain and urgency that come with flare-ups.
Bacterial infections may require antibiotics. Diarrhea triggered by inflammatory bowel disease, celiac disease, or food intolerances calls for managing the root condition rather than just treating symptoms. Your doctor can sort this out with stool tests, blood work, or other diagnostics depending on the pattern and severity.
Children Need a Different Approach
Standard anti-diarrheal medications are not safe for young children. Bismuth subsalicylate should not be used in kids under 12, and anti-diarrheal medicines in general are usually not helpful for infectious diarrhea in children. They can actually prolong the illness by preventing the body from clearing the infection.
For children, the priority is hydration. Oral rehydration solutions are the first-line treatment. Keep offering breast milk, formula, or their regular diet as tolerated. If a child’s diarrhea doesn’t improve within 24 hours, they develop a fever above 102°F (39°C), pass bloody or black stools, or seem unusually sleepy or unresponsive, that warrants prompt medical attention.
Warning Signs That Need Medical Attention
Most diarrhea clears up on its own or with basic OTC treatment. But certain symptoms signal something more serious. For adults, see a doctor if diarrhea lasts more than two days without improvement, you notice blood or black color in your stool, you develop a fever above 102°F, or you have severe abdominal or rectal pain. Any signs of dehydration that aren’t improving with oral fluids, like dizziness, weakness, or very dark urine, also warrant a visit.