For a typical bout of diarrhea, the most effective over-the-counter option is loperamide (sold as Imodium), which slows gut movement and can stop loose stools within hours. But medication is only part of the picture. Staying hydrated matters more than stopping the diarrhea itself, and what you eat (or avoid) during recovery plays a bigger role than most people realize.
Over-the-Counter Medications
Loperamide is the go-to for acute diarrhea. It works by slowing down the muscles in your intestinal wall, which gives your gut more time to absorb water and firms up your stools. The standard approach is 4 mg to start (two capsules), then 2 mg after each loose stool, up to a maximum of 8 mg per day when you’re self-treating. Don’t exceed that limit. At higher doses, loperamide can affect heart rhythm and cause serious side effects.
Bismuth subsalicylate (the active ingredient in Pepto-Bismol) takes a different approach. It reduces inflammation inside the intestine, decreases fluid flowing into the bowel, and can even kill some of the bacteria causing the problem. It’s a solid choice for milder cases or traveler’s diarrhea, though it works more gradually than loperamide. It can turn your tongue and stool black temporarily, which is harmless.
One important note for parents: loperamide should not be given to children under 3 years old. In clinical studies, serious side effects like severe drowsiness and intestinal paralysis occurred only in that age group. For children over 3 who aren’t dehydrated, loperamide may help, but oral rehydration is always the priority for kids.
Hydration Comes First
Diarrhea pulls water and electrolytes out of your body fast. If you’re having frequent watery stools, replacing those losses is more urgent than stopping the diarrhea. Plain water helps, but it doesn’t replace the sodium and potassium you’re losing.
The World Health Organization’s oral rehydration formula uses a specific balance of sodium and glucose (75 milliequivalents per liter of each) at a total concentration designed to maximize absorption. You don’t need to mix your own. Products like Pedialyte and DripDrop follow this principle. If you don’t have an oral rehydration solution on hand, clear broths and diluted fruit juices can bridge the gap, though they’re not as precisely balanced. Sports drinks tend to have too much sugar and not enough sodium, so they’re a secondary option at best.
Probiotics That Actually Help
Not all probiotics do much for diarrhea, but one strain has solid evidence behind it. Saccharomyces boulardii, a beneficial yeast (not a bacterium), has been shown in multiple studies to shorten diarrhea episodes by roughly 24 hours. A systematic review found it had the strongest effect on reducing diarrhea duration compared to other probiotic strains. You can find it sold under brand names like Florastor.
It works best when started early in the illness and taken alongside rehydration. It won’t replace loperamide for immediate symptom control, but it supports your gut’s recovery and may help prevent the diarrhea from dragging on.
What to Eat and What to Avoid
You don’t need to starve yourself. In fact, eating early in the course of diarrhea (within 12 hours of starting to rehydrate) leads to better outcomes than waiting. Research on refeeding consistently shows that delaying food doesn’t help your gut heal faster. If you’re breastfeeding an infant with diarrhea, continuing to nurse actually decreases stool volume and frequency.
Stick with bland, easy-to-digest foods. Plain rice, bananas, toast, boiled potatoes, and simple chicken or broth are all well tolerated. You’ve probably heard of the BRAT diet (bananas, rice, applesauce, toast), and while it’s a fine starting point, you don’t need to limit yourself strictly to those four foods.
What you should avoid:
- Dairy products. Lactose can be harder to digest during a bout of diarrhea, though mild cases usually tolerate small amounts fine. Full-strength milk is the most likely to cause trouble.
- Fried and fatty foods. Fat speeds up gut motility, which is the opposite of what you need right now.
- Sugar alcohols and artificial sweeteners. Sorbitol, erythritol, and aspartame can all pull extra water into your intestines. Check labels on sugar-free gum, candy, and diet drinks.
- Caffeine and alcohol. Both increase fluid loss and can irritate an already sensitive gut.
When Diarrhea Signals Something More Serious
Most cases of the runs resolve on their own within two to three days. But certain signs mean you shouldn’t just ride it out. Blood in your stool (not from hemorrhoids) is a red flag that warrants prompt medical attention. So is a fever that doesn’t have another obvious explanation, especially if it’s persistent.
Duration matters too. Diarrhea lasting more than four weeks is classified as chronic and points to something beyond a simple stomach bug, whether that’s a food intolerance, inflammatory bowel disease, or another underlying condition. Severe dehydration (dizziness, dark urine, rapid heartbeat, confusion) also calls for medical care rather than home treatment, particularly in young children and older adults who dehydrate faster.
If your diarrhea wakes you up at night, that’s another signal worth paying attention to. Nighttime symptoms are more commonly associated with inflammatory or infectious causes rather than the functional, stress-related kind.