This information is intended only to provide general guidance. It does not provide definitive medical advice. It is important that you consult your doctor about your specific medical condition.

Diarrhea refers to increased frequency of stools that are liquid or softer than usual. Almost everyone gets brief episodes of diarrhea once in a while. Diarrhea that has been present for less than 2 weeks is called acute diarrhea. Diarrhea lasting 2-4 weeks is called persistent diarrhea, and diarrhea lasting over 4 weeks is called chronic diarrhea. Abdominal cramps often accompany diarrhea and usually disappear temporarily after the bowel movement. Fever, blood in the stool, nausea, and bloating may also be present.

What causes diarrhea?

Diarrhea usually occurs because of a problem with the intestine, either the large intestine (the colon) or the small intestine. The causes of diarrhea depend on the duration of the diarrhea:

Acute diarrhea (less than 2 weeks in duration) is usually due to an infection by a virus (rotavirus, norovirus, and others), a bacteria (Salmonella, Shigella, Campylobacter, or certain disease-causing types of E. coli), or a parasite (Entamoeba histolytica, Cryptosporidium, Giardia, and others). It usually lasts 1 to 3 days but may persist for up to 2 weeks. C. difficile infection usually occurs after treatment with antibiotics. Viruses and bacterial infections usually get better on their own, but diarrhea due to parasites or C difficile may become chronic.

Chronic diarrhea is usually due to:

  • Irritable bowel syndrome
  • Inflammatory bowel disease such as Crohn's disease, ulcerative colitis, or microscopic/lymphocytic/collagenous colitis. See my separate webpages on these conditions.
  • Infections with parasites (amoeba/Entamoeba histolytica, Giardia, Cryptosporidium, Cyclospora, and others).
  • Clostridium difficile colitis (C. difficile colitis). This usually occurs when antibiotics are taken for an infection elsewhere in the body and eliminate many of the bacteria that normally live in the colon. The Clostridium difficile bacteria, which may have been present in small numbers, grows in to replace the missing bacteria and produces a toxin that damages the lining of the intestine and causes diarrhea and sometimes fever and abdominal pain. Clostridium difficile is contagious, but does not always cause symptoms. It may occur in the absence of exposure to antibiotics, and it may occur weeks or longer after exposure to an antibiotic.
  • After-effects of an infection that has passed. After a bacterial or viral infection has gone away, there may still be symptoms due to dysbiosis (an alteration in the microbiome, the many bacteria that normally live in the colon), temporary lactose (dairy) intolerance that can last a month or more after a viral infection, or post-infectious irritable bowel syndrome.
  • Celiac disease.
  • Food intolerance or sensitivity: Lactose (dairy) intolerance, fructose intolerance (the sugar found in many fruits, honey, carbonated beverages, and high-fructose corn syrup), gluten (wheat) sensitivity (see my web page on celiac disease), artificial sweeteners such as xylitol or sorbitol, or other food ingredients.
  • Reactions to medicines. Any medication can cause diarrhea, but common offenders are antibiotics, magnesium-containing antacids, and proton pump inhibitors (Nexium, Prilosec, Prevacid, and others).
  • Other digestive conditions such as bile salt induced diarrhea or chronic pancreatitis, in which there is a deficiency of digestive enzymes (proteins) made by the pancreas.

When should a doctor be seen because of diarrhea?

Severe diarrhea can result in dehydration, in which there is excessive loss of fluids, minerals, or chemicals called electrolytes. In adults, this causes severe weakness, dizziness or lightheadedness, dry mouth or skin, little or no urination, severe thirst, inability to get out of bed, and/or confusion. If any of these occur, you should consult your doctor. If vomiting is also present, dehydration occurs more quickly.

Other reasons for adults to contact your doctor include:

  • Persistent, constant abdominal pain.
  • Rectal pain.
  • Bloody stools.
  • Black, tarry stools.
  • Weight loss.
  • Fever over 102°F or shaking chills.
  • Severe diarrhea lasting more than 2 days or mild diarrhea lasting over 2 weeks.

Diarrhea lasting over 2 weeks, even if it is mild, is usually evaluated by a gastroenterologist, a specialist in digestive diseases, such as Dr. Albert Harary, who practices in New York City.

How is diarrhea treated?

Most acute diarrhea gets better quickly and does not require specific treatments. If you have not yet seen a doctor, you should drink enough fluid to make up for what you have lost; water is good, but should be supplemented by sugary liquids, broth, sports drinks, and Pedialyte. While the diarrhea is still present, a helpful diet consists of lots of liquids, white starches (white rice, white bread, white pasta, and potatoes without skins), and protein foods such as chicken, fish, red meat, and eggs, with avoidance of dairy, high-fat foods, and fiber (vegetables, fruits, and whole grains). Antibiotics are usually not needed. Over-the-counter medications such as Imodium (loperamide) and Pepto-Bismol should be used sparingly (1-2 times per day for one to two days). Imodium (loperamide) should not be used if there is bloody diarrhea, fever, abdominal distention, or steady pain. Probiotics may help hasten recovery after acute diarrhea.

Treatment of chronic diarrhea depends on what your doctor has found to be the cause of the diarrhea, although sometimes the doctor may make recommendations based on a suspected diagnosis. You should not go on a gluten-free diet before being tested by a doctor for celiac disease. While the diarrhea is still present, a helpful diet consists of lots of liquids, white starches (white rice, white bread, white pasta, and potatoes without skins), and protein foods such as chicken, fish, red meat, and eggs, with avoidance of dairy, high-fat foods, and fiber (vegetables, fruits, and whole grains).

To learn more about the treatment of diarrhea offered by Dr. Harary, please contact our New York City office today.