by Dr. Frank Jackson

Prebiotin Academy

Medical Concerns, Scientific Research and Diets


The Facts


Everyone has diarrhea at one time or another and everyone has their own idea of exactly what diarrhea is. Is it one liquid stool each day? Is it several soft, semi-formed stools each day? Or is it frequent, watery stools throughout the day and even the night? Most of the time, any of these can be called diarrhea.

Causes of Diarrhea

There are many causes of diarrhea. Fortunately, in most instances, this change in bowel habits is short lived and clears up on its own. In these cases, it is assumed that it is a virus infection or “something I ate”. Whenever diarrhea lasts more than two or three weeks, medical advice is generally recommended. Among the many known causes are:

  • Food – Most people have certain foods that may cause diarrhea. For hot pepper lovers (the chemical in it is called capaiscin), diarrhea often occurs the morning after. Many people are intolerant of milk and milk products so that even small amounts of the milk sugar lactose can cause diarrhea. Large amounts of fatty foods cause the same problem in other people. The obvious solution in all these instances is to avoid the offending agent.
  • Chemical Laxatives – Many people become dependent on laxatives early in life and use them on a daily basis. The names for the usual chemical stimulants are magnesium (Epsom salt), cascara (Nature’s Remedy), and phenolphthalein (Exlax, Correctol, Feen-A-Mint). Magnesium can be inadvertently ingested in various over-the-counter preparations such as Maalox or Mylanta. Sorbitol is an artificial sweetener that is used in sugar-free gum and prepared foods such as jams and jellies. Sorbitol, too, can act as a laxative.
  • Prescription Drugs – If a change in bowel habit occurs after taking a new drug, the physician should be contacted. In particular, antibiotics are known to cause diarrhea, at times quite severe. Diarrhea can develop up to one month after taking antibiotics.
  • Infection – There are over 1000 different types of bacteria that normally live quietly and beneficially in the large intestine. There are also viruses and other infectious agents that find their way into our bodies. Some of these can infect the intestinal tract and cause diarrhea. Virus infection is probably the most common cause of short-term diarrhea and, fortunately, it usually clears up on its own.  The robust immune system of our gut protects us. Some bacterial infections, such as salmonella, are serious and require medical evaluation. Salmonella commonly comes from contaminated food. There are parasites, such as giardia that attack the intestines. Giardia may be found in wild animals and in contaminated streams and well water. For people infected with the AIDS virus, there are a number of infections that can occur in the intestinal tract. Close medical follow-up is always required in these instances.
  • Traveler’s Diarrhea – The cause of traveler’s diarrhea is a toxic bacteria called E. Coli. It most often occurs in developing countries where sanitation is not good. This infection can often be prevented by avoiding fresh, uncooked produce and fruits. Fruits, such as oranges, that have protective skins are safe. In particular, tap water in any form and especially ice should be avoided. Bottled beverages are recommended. The physician should be contacted prior to travel to these countries to obtain more information on prevention and treatment.
  • Diseases – There are certain intestinal disorders that can cause chronic diarrhea. These include ulcerative and microscopic colitis, Crohn’s disease, diverticulosis, and even colon cancer. These are all serious diseases that require careful medical attention and treatment. It is a major reason why the cause of chronic diarrhea should always be known.
  • Irritable Bowel Syndrome (IBS) – IBS is a problem that occurs when the intestines, especially the colon, do not contract in a smooth, rhythmic manner. The contractions can be exaggerated in which case diarrhea occurs, or they may be sluggish and result in constipation. Sometimes there is alternating constipation and diarrhea. Emotional stress often aggravates these symptoms.


The cause and treatment of diarrhea may be very simple, such as discontinuing a food, a drug, over-the-counter medication or sorbitol-containing chewing gum. However, at times the diagnosis may be more difficult. Testing of blood and stool may be needed. X-rays and ultrasound may also be necessary. Often, colonoscopy is required to visually inspect the colon with a lighted, flexible tube. Testing depends on how severe and prolonged the condition is, and how the physician evaluates a specific case.


There are simple things that can be done at the beginning of a diarrhea episode which may help reduce symptoms. Taking only liquids by mouth and avoiding solid food may be helpful. Over-the-counter constipating agents, such as Pepto-Bismol, Kaopectate, or Imodium can also be tried. Dietary fiber or supplemental fiber products can be carefully tried. Bulking agents like polycarbosil (FiberCon) or methycellulose (Citrucel) may help. Soluble fibers fermented by bacteria in the colon are unpredictable. These include prebiotics, guar gum and psyllium (Metamucil). You should check with your physician on the use of these.


Diarrhea is a common problem which is usually not serious. If it is severe or persistent, a specific diagnosis should be sought. By working closely with the physician, effective treatment is usually available.