If you have watery diarrhea, replacing lost fluids is the first priority. Drink fluids, use an appropriate oral rehydration solution when advised, and return to usual food as appetite allows. Rehydration replaces lost fluid and salts but does not treat every cause of diarrhea. 12
Get prompt medical help for blood or black tarry stool, severe abdominal pain, repeated vomiting, dehydration or a marked change in alertness. NIDDK also advises adults to contact a clinician for diarrhea lasting more than two days, high fever or six or more loose stools in a day. Pregnancy, older age, immune suppression and recent antibiotics justify extra caution. This page is not a care plan for children. 3
What to do now
- Drink fluids. Follow the mixing directions if you use an oral rehydration product.
- Eat when you feel able. You can usually return to your normal food as your appetite comes back.
- Watch for dehydration and other warning signs. Notice whether you can drink, how much you urinate and whether you have dizziness, blood in the stool, severe pain or changes in alertness.
- Get medical advice when needed. Tell the clinician how long symptoms have lasted and about any recent medicines. 12
What should you drink?
Fluid and electrolyte replacement matters because watery stools can carry both out of the body. Oral rehydration solutions contain glucose and electrolytes. Use a packaged product exactly as directed; do not assume that extra powder makes it work better. People with kidney disease, diabetes, fluid restrictions or other relevant health conditions need advice about the suitable fluid and amount. 1
Small, frequent drinks may be easier to tolerate with nausea. Inability to keep fluids down, very little urine, marked dizziness or worsening weakness needs medical advice rather than repeated attempts to push through home care. 4
Ask a pharmacist for a suitable rehydration product if you are unsure what to use. Explain any fluid restrictions or medical conditions, and follow the mixing instructions carefully.
What can you eat—and should you fast?
Fasting is not routinely recommended. As appetite returns, most people can go back to their usual diet. Alcohol, caffeine, very sugary drinks, fatty foods or lactose may make symptoms harder to tolerate for some people during recovery. That does not establish a permanent intolerance. 2
Choose foods you can tolerate. Avoid a prolonged restrictive diet without medical advice.
Can you take loperamide or bismuth?
NIDDK identifies loperamide and bismuth subsalicylate as nonprescription options for some adults with acute diarrhea. It advises against routine use in children or when bloody stool or fever is present. Symptoms that worsen or persist while taking them need assessment. 1
Check the actual product directions and suitability with a pharmacist, including age, pregnancy, other medicines and medical conditions. Do not take more to conceal a persistent problem. These medicines do not make every cause of diarrhea safe to manage at home.
Do you need antibiotics or a probiotic?
Antibiotics do not treat norovirus; whether another cause needs them depends on the diagnosis. CDC describes norovirus illness as commonly improving in one to three days, but the duration is not a diagnostic test. 5
A probiotic is not automatically necessary. NIDDK describes ongoing research and notes that many doctors and professional societies do not consider the evidence sufficient to support probiotics for treating or preventing diarrhea. The exact condition and product matter. 1
Does watery diarrhea without fever need less attention?
No fever does not rule out dehydration, medicine effects or other illness. Blood, pain, drinking ability, urine changes and duration remain important. Watery or forceful diarrhea alone does not identify a particular infection. 6
How do you reduce spread?
Use soap and water for handwashing, clean affected surfaces and avoid preparing food for others while ill. CDC emphasizes that alcohol hand sanitizer is not a substitute for handwashing when managing norovirus risk. UK NHS guidance uses at least 48 hours after the last diarrhea or vomiting episode before return to work or school; clinical and food-handling roles may have additional rules. 74
What information helps when you call?
Describe the first day, approximate watery stools per day, vomiting, fever, blood, ability to drink, urine changes, travel and recent antibiotics or other medicines. Give the details you remember; you do not need a complete diary before seeking help.
For an ongoing episode, see diarrhea for three days, four days or a week. For a single soft movement, read loose stool versus diarrhea. Neither comparison overrides the warning signs above.