Yes, several effective medicines treat diarrhea, and most are available without a prescription. The two main over-the-counter options are loperamide (sold as Imodium) and bismuth subsalicylate (sold as Pepto-Bismol and Kaopectate). Which one you should reach for depends on the type of diarrhea you have, what’s causing it, and whether you’re treating yourself or a child.
Over-the-Counter Options
Loperamide works by slowing the speed at which food and fluid move through your intestines. That gives your body more time to absorb water, which means fewer trips to the bathroom and more solid stools. The maximum recommended dose for adults is 8 mg per day when using the OTC version. The FDA has warned that taking more than directed can cause serious heart problems, so sticking to the label dose matters.
Bismuth subsalicylate takes a different approach. It balances fluid movement in the intestines, reduces inflammation, and limits the growth of bacteria and viruses in the stomach and gut. It’s a good option for milder cases or when nausea accompanies the diarrhea. However, because it contains a compound related to aspirin, it comes with some important cautions. If you have a bleeding disorder, take blood thinners, or are sensitive to aspirin, this one isn’t for you. It can also interact with common pain relievers like ibuprofen and naproxen, so check labels carefully to avoid doubling up on salicylates.
When OTC Medicine Isn’t Safe to Use
Not all diarrhea should be treated with these medicines. If you see blood in your stool, skip the loperamide. Slowing down your gut when a serious bacterial infection is present can actually make things worse by keeping the harmful bacteria inside longer. Clinical guidelines from the American Academy of Family Physicians are clear on this point: antimotility agents like loperamide should be restricted to watery, non-bloody diarrhea. For infections caused by certain dangerous strains of E. coli, these medicines should be avoided entirely.
Viral diarrhea, the kind that comes with a stomach bug, typically doesn’t respond to antibiotics. It runs its course in a few days with fluids and rest. Using loperamide to manage symptoms while you recover is generally fine as long as there’s no blood or high fever.
Prescription Medicines
When diarrhea is caused by a specific bacterial or parasitic infection, a doctor may prescribe antibiotics or antiparasitic drugs. Most bacterial diarrhea actually clears on its own without antibiotics, but severe or persistent infections do need targeted treatment. Your doctor can determine the cause through stool testing.
For traveler’s diarrhea, the CDC recommends reserving antibiotics for severe cases only. If your doctor does prescribe them, take the full course exactly as directed.
Chronic diarrhea that lasts weeks or keeps coming back often signals an underlying condition like inflammatory bowel disease or irritable bowel syndrome. These require a different treatment strategy altogether, usually managed by a gastroenterologist who tailors a plan to the specific diagnosis. The medicines used for these conditions are quite different from what you’d pick up at a pharmacy for a short bout of loose stools.
Probiotics as a Supplement
Probiotics won’t stop diarrhea the way loperamide does, but certain strains have solid clinical evidence behind them. Two stand out: Lactobacillus rhamnosus GG (often called LGG) and Saccharomyces boulardii, a beneficial yeast. In studies of acute infectious diarrhea, both reduced the duration of symptoms by roughly one day.
Their strongest evidence is for antibiotic-associated diarrhea, the loose stools that often develop as a side effect of antibiotic treatment. A large review found that Saccharomyces boulardii cut the risk of antibiotic-associated diarrhea in adults from about 17% to 8%, and in children from about 21% to 9%. LGG showed similar benefits, reducing risk from roughly 22% to 12%. If you’re starting a course of antibiotics and want to lower your chances of diarrhea, taking one of these probiotics from day one is a reasonable strategy.
Treating Children Differently
Children with diarrhea need a different approach than adults. The priority is preventing dehydration, not stopping the diarrhea itself. Oral rehydration solutions are the first-line treatment for kids with viral gastroenteritis. Once a child is rehydrated, returning to a normal, age-appropriate diet is recommended. That means complex carbohydrates like rice, bread, and potatoes, plus lean meats, yogurt, fruits, and vegetables.
One common mistake parents make is restricting a child’s diet to clear liquids or the old BRAT diet (bananas, rice, applesauce, toast) for too long. Giving only clear liquids for several days can actually prolong diarrhea because the gut isn’t getting enough nutrients, resulting in what’s called “starvation stools.” Most children also tolerate full-strength milk just fine during a bout of diarrhea, so there’s no need to switch to diluted milk unless the child has a known cow’s milk allergy. High-fat foods are harder to absorb and are worth avoiding until things settle down.
Signs That Need Medical Attention
For adults, diarrhea that lasts more than two days without improvement warrants a call to your doctor. The same goes for signs of dehydration: excessive thirst, very dark urine, little or no urination, dizziness, or severe weakness. Bloody or black stools and severe abdominal pain also need professional evaluation.
For children, the timeline is shorter. Seek medical attention if a child’s diarrhea hasn’t improved within 24 hours, if an infant has no wet diaper for three or more hours, or if a fever climbs above 102°F. Physical signs to watch for include a sunken appearance around the eyes, cheeks, or abdomen, and skin that doesn’t bounce back quickly when you gently pinch it. Bloody or black stools in a child, or a child who seems unusually sleepy or unresponsive, needs prompt care.