For most cases of acute diarrhea, an over-the-counter medication like loperamide (Imodium A-D) or bismuth subsalicylate (Pepto-Bismol) will slow things down while your body fights off whatever triggered it. But the single most important thing you can take is fluid, because dehydration is the real danger with diarrhea, not the diarrhea itself. What works best depends on the cause, your age, and how severe your symptoms are.
Loperamide: The Fastest OTC Option
Loperamide slows the movement of your gut, giving your intestines more time to absorb water and firm up your stools. It’s the go-to for quick relief when you need to get through a workday or a flight. The FDA-approved maximum for over-the-counter use is 8 mg per day for adults. Most products come in 2 mg doses, so that’s a maximum of four caplets in 24 hours.
There are situations where you should skip loperamide entirely. If your stools contain blood, or you have a fever alongside the diarrhea, slowing your gut down can actually trap the infection inside. In those cases, your body is using diarrhea to flush out harmful bacteria, and you want to let that process happen while staying hydrated.
Bismuth Subsalicylate for Milder Cases
Bismuth subsalicylate, sold as Pepto-Bismol or Kaopectate, is a gentler option that also helps with the nausea and stomach cramping that often accompany diarrhea. It works differently from loperamide and tends to be better suited for mild cases or an upset stomach with loose stools rather than urgent, watery diarrhea.
A few important safety notes: bismuth subsalicylate contains a compound related to aspirin. If you’re allergic to aspirin, or you’re already taking aspirin or other salicylate-containing medications, combining them can lead to overdose. Check the labels of any other OTC or prescription medicines you’re taking. Children under 12 should not take bismuth subsalicylate at all. For teenagers recovering from the flu or chickenpox, it carries a risk of Reye’s syndrome, a rare but serious condition affecting the brain and liver. The same applies to any aspirin-containing product in anyone under 16.
Fluids and Electrolytes Matter More Than Food
Replacing lost fluid is the cornerstone of treating any bout of diarrhea. Water alone helps, but when you’re losing a lot of fluid, you’re also losing sodium, potassium, and other electrolytes. Oral rehydration solutions (like Pedialyte or store-brand equivalents) replace both water and electrolytes in the right ratio. Sports drinks work in a pinch for adults, though they contain more sugar than ideal. Broth is another good option because it provides sodium.
Signs that dehydration is setting in include extreme thirst, dark-colored urine, urinating less than usual, dizziness, and fatigue. In infants, watch for no wet diapers for three hours or more, no tears when crying, or a sunken soft spot on the skull. These signs mean you need to push fluids aggressively or seek medical help.
What to Eat (and What You Can Skip)
The old advice to stick to bananas, rice, applesauce, and toast (the BRAT diet) is no longer the standard recommendation. Most experts, including those at the National Institute of Diabetes and Digestive and Kidney Diseases, say you can return to your normal diet as soon as you feel ready to eat. There’s no benefit to restricting yourself to bland foods. Children with acute diarrhea should eat their usual age-appropriate diet, and infants should continue breast milk or formula.
That said, it’s reasonable to temporarily avoid greasy, very spicy, or high-fiber foods if they seem to make things worse. Dairy can also be harder to digest during a bout of diarrhea for some people. But the overall guidance is simple: eat when you’re hungry, eat what you normally eat, and don’t fast.
Probiotics as a Supplement
Certain probiotics can shorten the duration of acute diarrhea, particularly in children. The most studied strain is Saccharomyces boulardii, a beneficial yeast. In a randomized, placebo-controlled trial published in The Pediatric Infectious Disease Journal, children taking S. boulardii recovered from diarrhea in about 66 hours compared to 95 hours in the placebo group, a difference of roughly a full day. They also reached their first normal-consistency stool about 23 hours sooner.
For adults, the evidence is less dramatic but still suggests modest benefit. Probiotics are generally safe and available without a prescription. Look for products specifically containing S. boulardii or Lactobacillus rhamnosus GG, which have the strongest research behind them for diarrhea specifically. They work best when started early in the illness.
When Antibiotics Are Needed
Most diarrhea is caused by viruses and clears up on its own within a few days. Antibiotics won’t help with viral diarrhea. But bacterial diarrhea, particularly traveler’s diarrhea picked up abroad, sometimes requires antibiotic treatment. The CDC considers antibiotics appropriate when diarrhea is moderate enough to interfere with your activities, or severe enough to be incapacitating.
Doctors typically prescribe azithromycin as the first choice for severe or bloody traveler’s diarrhea. It’s also preferred in Southeast Asia and other regions where bacteria tend to be resistant to other antibiotics. These are prescription medications, so if you’re traveling internationally and concerned about this risk, it’s worth talking to a doctor before your trip about carrying a course of antibiotics with you.
Zinc for Children With Diarrhea
The World Health Organization recommends zinc supplementation for children with acute diarrhea: 20 mg per day for 10 to 14 days for children over six months, and 10 mg per day for infants under six months. Zinc helps reduce the severity and duration of the episode and may protect against future bouts in the following weeks. This recommendation is most relevant in low-resource settings where zinc deficiency is common, but it’s a safe and inexpensive option regardless.
Red Flags That Need Medical Attention
Most diarrhea resolves within a couple of days. But certain symptoms signal something more serious. For adults, contact a doctor if diarrhea lasts more than two days, you develop a high fever, you’re passing six or more loose stools per day, or you notice blood, pus, or black tarry stools. Severe abdominal or rectal pain and signs of dehydration also warrant prompt attention.
For children, the timeline is shorter. Diarrhea lasting more than one day, any fever in infants, refusal to eat or drink for more than a few hours, or signs of dehydration like sunken eyes, drowsiness, or dry mouth all call for a doctor’s evaluation quickly. Children and infants dehydrate faster than adults, and what seems like a mild illness can escalate in hours.