For most cases of acute diarrhea, over-the-counter medications like loperamide (Imodium) or bismuth subsalicylate (Pepto-Bismol) will slow things down while your body fights off whatever caused the problem. But the single most important thing you can do is replace lost fluids. Diarrhea pulls water and electrolytes out of your body fast, and dehydration is what makes a mild illness feel miserable or even dangerous.
Over-the-Counter Medications
Loperamide is the most widely used anti-diarrheal medication. It works by slowing the movement of your intestines, giving your gut more time to absorb water back from stool. It also tightens the anal sphincter, which helps with the urgency that sends you running to the bathroom. The standard approach for adults is to take 4 mg (two caplets) after the first loose stool, then 2 mg after each additional loose stool, up to a maximum of 16 mg in a day. Most people find relief well before reaching that limit. If you’re still having symptoms after two days with no improvement, it’s time to see a doctor rather than keep dosing.
Bismuth subsalicylate (the active ingredient in Pepto-Bismol and Kaopectate) takes a different approach. It reduces the flow of fluids into the bowel, calms intestinal inflammation, and has mild antimicrobial properties that can help kill some of the organisms causing the problem. This makes it a reasonable choice for traveler’s diarrhea or food poisoning. One important caution: bismuth subsalicylate contains a compound related to aspirin, so it should not be given to children or teenagers, especially those with flu or chickenpox symptoms, due to the risk of Reye’s syndrome, a rare but serious condition affecting the brain and liver.
Fluids and Electrolyte Replacement
No medication matters as much as staying hydrated. Every watery stool pulls sodium, potassium, and chloride out of your body along with the water. Plain water helps, but it doesn’t replace those electrolytes. Oral rehydration solutions (sold as Pedialyte, DripDrop, or similar products) are specifically designed to match the ratio your gut absorbs most efficiently. You can also sip clear broths, diluted juice, or coconut water throughout the day.
Signs that dehydration is getting ahead of you include dark yellow urine, dry mouth, dizziness when standing, and feeling unusually tired. In children, watch for fewer wet diapers, no tears when crying, or unusual drowsiness. If you can’t keep fluids down because of vomiting, take small sips every few minutes rather than gulping a full glass.
What to Eat (and What to Skip)
The classic BRAT diet (bananas, rice, applesauce, toast) has been recommended for decades, though there are no studies comparing it to other approaches. It’s fine for the first day or two when your stomach is most unsettled, but there’s no reason to limit yourself to just those four foods. As Harvard Health notes, a less restrictive diet often makes more sense for recovery.
Once your appetite starts returning, add bland, easy-to-digest foods that also provide protein and nutrients: cooked carrots, butternut squash, sweet potatoes without skin, avocado, skinless chicken, fish, and eggs. These give your body what it needs to recover without irritating your gut. For the first few days, avoid dairy, fatty or fried foods, caffeine, alcohol, and high-fiber raw vegetables, all of which can worsen loose stools.
Probiotics
Certain probiotic strains can shorten how long diarrhea lasts. The best-studied is Saccharomyces boulardii, a beneficial yeast rather than a bacterium. In a randomized controlled trial, children with acute diarrhea who received S. boulardii recovered in about 66 hours on average, compared to 95 hours for the placebo group. That’s roughly a day and a half faster. Within three days, over 80% of the probiotic group had recovered, versus only 16% of those on placebo.
S. boulardii is available over the counter (sold as Florastor and generic versions). Lactobacillus-based probiotics also have some supporting evidence, though the data is strongest for S. boulardii in acute diarrhea. Probiotics work best when started early and taken alongside adequate fluids.
Prescription Treatments
Most acute diarrhea resolves on its own within a few days and doesn’t need a prescription. But certain situations call for one. Traveler’s diarrhea caused by specific bacteria can be treated with rifaximin, a gut-targeted antibiotic. The typical course is 200 mg three times daily for three days. Because it barely enters the bloodstream and acts almost entirely inside the intestines, it tends to cause fewer side effects than systemic antibiotics.
If diarrhea turns out to be caused by a bacterial infection like Salmonella, Campylobacter, or C. difficile, your doctor may prescribe targeted antibiotics. Importantly, for C. difficile infections, antimotility drugs like loperamide were long considered off-limits because of concerns about trapping toxins in the gut. More recent evidence suggests that using them alongside appropriate antibiotic treatment does not appear to increase the risk of complications and may reduce the total number of diarrhea days, but this is a decision to make with a doctor, not on your own.
Special Considerations During Pregnancy
If you’re pregnant, the safest first step is oral rehydration and dietary changes. Loperamide has not shown adverse effects in animal studies, but human data is limited and conflicting. Some experts consider it acceptable in the lowest effective dose when symptoms are severe enough to be disabling, but it’s not a casual first choice. Bismuth subsalicylate should be avoided entirely during pregnancy because of its aspirin-related component. If diarrhea persists beyond a day or two during pregnancy, contact your provider early rather than self-treating.
Signs That Need Medical Attention
For adults, see a doctor if diarrhea lasts more than two days without any improvement, if you develop a fever above 102°F (39°C), if you notice blood or black color in your stool, or if you have severe abdominal or rectal pain. For children, the timeline is shorter: seek care if diarrhea doesn’t improve within 24 hours, or if any of those same warning signs appear. Bloody stool in particular can signal a bacterial infection or inflammatory process that over-the-counter medications won’t resolve.