Probiotics are live microorganisms that are purposefully ingested by humans to improve their health—the thought is that probiotics improve “digestive health.” The specific microorganisms are commonly of the genera Lactobacillus, Bifidobacterium, and/or Bacillus. For instance, one or more probiotic preparations may be taken to re-populate the bowel with normal bacteria (in other words, to have the “friendly bacteria” represent more than 85 percent of the bacteria present) after a person takes a course of antibiotics, which strip the bowel of its normal microorganisms. Probiotics have been recommended to diminish the symptoms of irritable bowel syndrome.

A common question is whether or not probiotics are useful as part of the treatment of infectious diarrhea. To attempt to answer this question, Jeffrey Horn, MD prepared a brief article entitled “Do Probiotics Reduce the Duration and Symptoms of Acute Infectious Diarrhea” (Annals of Emergency Medicine 58[5]:445-46, 2011). In this analysis, he reviewed 63 published studies that looked at the effect of probiotic versus placebo or no probiotic on the duration and symptoms of acute infectious diarrhea. Specifically noted were primary outcomes of duration of diarrhea, diarrhea lasting greater than or equal to four days, and stool frequency on day two after intervention.

In this evaluation, probiotics appear to reduce stool frequency and shorten the duration of acute infectious diarrhea by one day.  The author notes that these results were obtained when probiotics were used along with standard rehydration therapy. He also notes that probiotics were not associated with any significant adverse effects. No mention is made of whether or not probiotics were administered with or without antibiotics or any other specific therapy, such as an antimotility agent. It is presumed that these were not used, but that the published studies evaluated were limited to the consideration of probiotics versus no probiotics, without other confounding factors. 

So, should we add probiotics to the recommendations for treating acute infectious diarrhea? It appears safe to do this and not to pose any harm to the patient. The drugs can be obtained inexpensively compared to the cost of an additional day of diarrhea, if that means a day lost to activities that are important to the patient or that generate revenue. If antibiotics are going to be used to treat infectious diarrhea, until further notice, it makes sense to wait for the antibiotic course to be completed or nearly completed prior to initiating administration of the probiotic(s). For how long should the probiotic be taken? Some people take probiotics every day, so the course of therapy can probably not be too long. At a minimum, it would be recommended to take a dose of the probiotic(s) once or twice a day for at least 7 to 14 days.

Reprinted with permission by the Author from Healthline.com