What is diarrhea?
Diarrhea, is derived from the Greek word “to flow through”, and is a common problem for many people. Because the range of normal stools is broad, it is not defined by the number of stools a person passes per day. In general, acute diarrhea is defined as less than 14 days in duration and chronic diarrhea is defined as more than 30 days in duration.

What are the symptoms of diarrhea?
Symptoms may be mild, such as painless and watery bowel movements, or more severe. “Alarm” symptoms which generally require medical evaluation are severe abdominal pain, high fever, bloody stools, or symptoms of dehydration (dizziness, dry mouth and tongue, rapid pulse, dark urine).

What are the causes of diarrhea?

  • Infection, from viruses, bacteria, and less often, protozoa. Viral infections are common, but the exact type of virus causing the diarrhea can rarely be identified. Bacterial infections include Campylobacter, Salmonella, Shigella, and E. coli O157:H7. Previous antibiotic use or underlying inflammatory bowel disease can be associated with Clostridium difficile infection. Protozoa include Giardia, Entamoeba histolytica, and Cryptosporidium.


  • Medications, including over-the-counter drugs and supplements.
  • Irritable bowel syndrome, from disordered motility and erratic fluid absorption.
  • Infection. See above. Some infectious agents can cause prolonged symptoms
  • Inflammatory bowel disease (ulcerative colitis, Crohn’s disease)
  • Ischemic colitis (This results from low blood flow to the colon).
  • Microscopic colitis (lymphocytic or collagenous colitis).
  • Malabsorption syndromes (from conditions such as lactose intolerance, celiac disease, or chronic pancreatitis, bacterial overgrowth, or previous surgery to the small bowel or colon).
  • Post-cholecystectomy (following removal of the gallbladder)
  • Hyperthyroidism
  • Diabetes mellitus
  • Radiation injury to the small bowel or colon
  • Colon cancer
  • Neuroendocrine tumors (gastronoma, VIPoma, carcinoid syndrome)

What type of evaluation can I expect?
This depends on the duration and severity of your symptoms. Your provider may order blood work including a complete blood count, thyroid function tests, serum electrolytes, and a blood test for celiac disease. A variety of stool tests may be ordered to search for an infectious agent. A flexible sigmoidoscopy or colonoscopy is frequently indicated, but this depends on your age, severity of symptoms, and the timing and results of any previous colonoscopies. Occasionally, you may be asked to collect your stools for 2-3 days in order to document fat malabsorption. Breath tests may be ordered to investigate conditions such as lactose intolerance and bacterial overgrowth.

What is the treatment?
The treatment of your diarrhea depends on its cause. Mild symptoms can often be treated at home. More severe symptoms may warrant a medical evaluation and occasionally hospitalization.

Mild symptoms:

  • Drink plenty of clear liquids such as water, flat ginger ale, or sports drinks
  • Avoid caffeine-containing beverages like coffee, because coffee makes the bowel work faster.
  • Avoid milk, which can be hard to digest during a bout of diarrhea
  • Take certain prescribed medications (such as antibiotics for infection). Don’t take any diarrhea medications without asking your health care provider first.
  • Fast (avoid food) or eat a special diet called BRAT (short for bananas, rice, applesauce, and toast).

Moderate to severe symptoms (pain, high fever, bloody stool, symptoms of dehydration).

  • Contact your health care provider, as specific additional therapy may be needed.