Probiotics are friendly microbes that can be found in supplements and foods like yogurt, sauerkraut, kefir, tempeh and natto (two foods made from fermented soybeans).  Diarrhea has been linked to an upset in the balance of friendly bacteria in the gut, and studies have suggested that supplementation with probiotics may help.

Inside the human digestive system are at least 400 types of beneficial bacteria that help prevent the growth of harmful bacteria.  These friendly microbes also support a healthy digestive system because they facilitate the breakdown of food and help to maintain a healthy intestinal lining.

Infectious Diarrhea
In 2000, a study was conducted on 287 children that were hospitalized with infectious diarrhea.  One group was given a probiotic-enhanced solution for rehydration, while the other group was given the rehydration solution alone.  The children who received probiotics recovered sooner and were able to leave the hospital earlier than the children who did not.  In fact, it has been shown that taking probiotics can help lower the duration of infectious diarrhea by up to two days.

Diarrhea Associated with Antibiotic Use
Because taking antibiotics can disrupt the normal balance of friendly bacteria within the gut, diarrhea is sometimes a side effect.  Recent studies show that taking probiotics before and during treatment with antibiotics can lower the risks for associated diarrhea.  According to research, the two probiotic types that seem to be most effective for this are Saccharomyces boulardii and Lactobacillus GG.

Traveler’s Diarrhea
Diarrhea that is a result of contaminated water or food affects many travelers each year.  This type of diarrhea can become chronic and lead to irritable bowel syndrome.  A report in 2007 examining data from twelve studies found that probiotics can significantly lower risks for this type of diarrhea, with the most effective types being S. boulardii, Lactobacillus acidophilus and Bifidobacteria bifidum.

Diarrhea Caused by Clostridium Difficile
C. difficile is an intestinal infection that can result in severe diarrhea and colitis.  Preliminary evidence indicates that probiotics in the form of Saccharomyces boulardii and Lactobacillus GG may be helpful in the prevention of this infection.  Experts suggest however, that supplementation would probably be most helpful with recurring infection after standard treatment has been issued.

A large study in 1994 looked at C. difficile patients with recurrent diarrhea.  One group was given a probiotic and the other, a placebo.  Only 9 in 26 people given probiotics experienced a recurrence, while 22 in 34 of the placebo patients experienced recurrence of diarrhea.

While probiotics appear to be helpful for diarrhea associated with many health conditions, there are some types of diarrhea they will not help, such as that associated with inflammatory bowel disease and Crohn’s disease.

Probiotic foods and supplements are currently available in most health food stores, in many grocery stores and through natural supplement websites.  Yogurt and probiotic dairy drinks are readily available, and supplements can be found in the form of capsules, powders and liquids.  When choosing a product, it is essential to find one that contains organisms that have been tested for effectiveness.