The fastest relief for an upset stomach with diarrhea comes from a combination of staying hydrated, eating bland foods, and using the right over-the-counter medication if needed. Most cases caused by a stomach virus or food poisoning resolve on their own within one to three days, but what you eat, drink, and take during that window makes a real difference in how you feel.
Start With Fluids, Not Food
Diarrhea pulls water and electrolytes out of your body fast, and dehydration is the main reason people end up feeling weak, dizzy, or significantly worse than the stomach bug alone would cause. Your first priority is replacing what you’re losing. Take small, frequent sips rather than gulping large amounts at once, which can trigger nausea.
Water alone isn’t ideal because it doesn’t replace the sodium, potassium, and chloride leaving your body. Oral rehydration solutions are the gold standard. Coconut water is a popular natural alternative, and it does contain roughly 160 mg of potassium per 100 ml, comparable to commercial rehydration drinks. However, it’s lower in sodium (25 mg vs. 35 mg per 100 ml in oral rehydration solutions) and much lower in chloride, so it’s a decent supplement but not a full replacement if you’re losing a lot of fluid. Diluted broths, weak tea, and electrolyte drinks all help. Avoid coffee, alcohol, and sugary sodas, which can make diarrhea worse.
What to Eat (and What to Skip)
You don’t need to force yourself to eat if you have no appetite, but once you’re ready, stick to soft, low-fiber foods that won’t irritate your gut. Good choices include white rice, plain toast or crackers made with refined flour, bananas, applesauce, boiled potatoes, eggs, broth-based soups, and lean proteins like baked chicken or whitefish. Creamy peanut butter, plain pasta, and gelatin are also well tolerated.
The foods to avoid matter just as much. Raw vegetables, salads, whole grains, nuts, seeds, and high-fiber cereals all speed up digestion and can worsen diarrhea. Fried or greasy foods, strong spices, garlic, and heavy dairy like ice cream or aged cheeses are common triggers for more cramping. Dried fruits and gas-producing vegetables like broccoli, cabbage, and cauliflower should wait until you’ve been symptom-free for a day or two.
Over-the-Counter Medications
Two widely available medications target diarrhea and upset stomach in different ways.
Loperamide (the active ingredient in Imodium) works by slowing down intestinal movement, which gives your body more time to absorb water and firms up stools. It’s effective for controlling frequent, watery diarrhea in adults. Don’t use it in children under 2, and elderly adults should use it with caution because of a small risk of heart rhythm problems. If your diarrhea hasn’t improved after two days of use, or you develop a fever, stop taking it.
Bismuth subsalicylate (the active ingredient in Pepto-Bismol) treats both upset stomach and diarrhea. It coats the stomach lining and has mild anti-inflammatory properties. One important safety note: it contains a compound related to aspirin and should not be given to children under 12. It should also be avoided in children or teenagers with flu or chickenpox symptoms because of the risk of Reye’s syndrome, a rare but serious condition affecting the brain and liver.
Probiotics Can Shorten Recovery
Certain probiotic strains can reduce how long diarrhea lasts, particularly when it’s caused by a virus. One well-studied strain, found in many commercial probiotic supplements and some yogurts, is recommended by international guidelines for children with gastroenteritis. Clinical trials show that diarrhea intensity drops within hours of starting this probiotic, not days. Another well-supported option is a yeast-based probiotic commonly sold under the brand name Florastor. Both work by helping restore the balance of gut bacteria and strengthening the intestinal lining against further damage.
Look for products that list specific strains and colony counts on the label. Generic “probiotic blend” products without strain-level detail are harder to evaluate.
How Long This Typically Lasts
The timeline depends on the cause. Norovirus, the most common culprit behind the “stomach flu,” usually produces symptoms within one to two days of exposure and clears up within a day or two after that. Rotavirus, which is more common in infants and young children, tends to last longer: three to eight days from symptom onset. Bacterial food poisoning varies widely but often resolves within 24 to 48 hours.
During this window, your gut lining is recovering, so reintroduce normal foods gradually even after diarrhea stops. Jumping straight back to spicy, fatty, or high-fiber meals can restart symptoms.
Signs That Need Medical Attention
Most stomach bugs are uncomfortable but not dangerous. However, certain symptoms signal something more serious. For adults, see a doctor if diarrhea persists beyond two days, you notice blood or black color in your stools, you have severe abdominal or rectal pain, or your temperature reaches above 101°F (38°C). For children, the threshold is tighter: seek care if diarrhea doesn’t improve within 24 hours, the child shows signs of dehydration (dry mouth, no tears, reduced urination), or a fever above 101°F develops. Bloody or black stools in a child warrant immediate attention.