What diarrhea is and how it varies
Diarrhea is loose or watery stool three or more times a day. Most often it is acute and caused by a gut infection: viruses, bacteria, or simply food that was not fresh. This kind usually clears up within 5 to 7 days, although vomiting settles sooner. Less often diarrhea drags on because of lactose intolerance, irritable bowel syndrome, medicines or chronic bowel disease. The main danger of any diarrhea is losing fluid.
Diarrhea and vomiting
Loose stools with nausea and vomiting most often mean a gut infection or food poisoning. Vomiting usually passes within a day or two; see Nausea and vomiting for more. The key in this period is to drink small sips so you do not become dehydrated.
Diarrhea with a fever
A fever with diarrhea points to an infection. In children a common cause is rotavirus infection, in adults bacteria and viruses from food and water. If the fever is high, lasts more than a day or the stool is bloody, see a doctor. For more on fever, see Fever. If diarrhea and a high fever appear after a trip to a place with poor sanitation, tell the doctor, who may need to rule out typhoid fever, for example.
Diarrhea with blood or mucus
Blood in the stool, black stool or a lot of mucus is not something to wait out at home. Blood can appear with a bacterial infection, inflammatory bowel disease, hemorrhoids or fissures, but it cannot be sorted out without an examination. In a child, blood in the stool means a doctor visit the same day.
Diarrhea in a child or baby
In children diarrhea is dangerous because they lose fluid quickly. Warning signs are refusing to drink or eat, passing urine rarely, a dry mouth, crying without tears, drowsiness, sunken eyes and a high fever. A baby under one year, or a child who has stopped feeding, needs care the same day. Breastfeeding should continue. See a pediatrician, and do not give children medicines for diarrhea without a doctor.
Diarrhea after antibiotics
Antibiotics upset the balance of gut bacteria, and loose stool can appear during treatment or weeks afterward. Mild diarrhea often clears up by itself, but if the stool is watery and frequent, with a fever and belly pain (see Abdominal pain), tell your doctor. Do not stop a prescribed antibiotic without their advice.
Diarrhea that does not go away
If loose stool lasts more than two weeks, keeps returning for weeks, or comes with weight loss, night-time urgency or anemia, see a gastroenterologist. Possible causes include lactose intolerance, celiac disease, irritable bowel syndrome and inflammatory bowel disease. If diarrhea alternates with constipation, see Constipation and Bloating.
What you can do before the visit
- Drink plenty and often: water, weak tea, oral rehydration solutions from a pharmacy. If you feel sick, take small sips.
- Eat light food when you can and avoid fatty and spicy dishes. Fruit juice and fizzy drinks can make diarrhea worse.
- Do not take stool-stopping medicines or antibiotics without a doctor, especially with a fever or blood in the stool, and do not give them to children.
- Wash your hands often with soap, and do not prepare food for others until the symptoms have passed, and for a few days after, because gut infections are contagious.
- Note how many stools you have had, what they look like, whether there is blood or a fever, what you ate and took, and how often you pass urine.
How a doctor finds the cause
The doctor asks about duration, the look of the stool, food, trips, medicines and contact with sick people, then examines you and assesses dehydration. A stool test and blood tests may follow, and for lasting diarrhea tests for lactose intolerance or celiac disease, an ultrasound and a colonoscopy. Treatment depends on the cause; severe dehydration may call for a drip.