A probiotic is defined as:

"A microorganism (such as a bacteria or yeast) that when ingested maintains or restores beneficial bacteria to the digestive tract."
 Probiotics are also often termed "beneficial bacteria") and have been used for treatment in such conditions as:

  • Diarrhea
  • Traveler's diarrhea
  • Constipation
  • Ulcerative colitis
  • Irritable bowel syndrome
  • Treatment of Helicobacter pylori (H. pylori)
  • Respiratory infections

Probiotics For Constipation

While the most evidence of benefit for probiotics is for the treatment of antibiotic associated diarrhea, there is a good amount of positive evidence for probiotic use in constipation.

A study published in the The American Journal of Clinical Nutrition reviewed previous studies and found that probiotics may help increase whole gut time and improve stool consistency and frequency.  The specific strain of the bacteria found most likely to be beneficial was Bifidobacterium lactis. B. lactis increased bowel movements by 1.5 bowel movements/week. Overall, whole gut time was decreased by 12.4 hours, meaning the food took less time to travel through the whole gastrointestinal tract.  

How Do Probiotics Work

Probiotics are thought to work via mechanisms, including:

  • Compete with disease causing bacteria for space and nutrients in the GI tract (i.e. "block" pathogenic bacteria from proliferating).
  • Immunomodulating (i.e. stimulating or supressing the immune system).
  • Improve digestion via metabolism changes.

Where To Find Probiotics

Probiotics can be found in yogurt, dietary supplements, kefir and fermented food.  They are also available as dietary supplements. Probiotics are generally well tolerated with the most common side effects of bloating and flatulence (gas) being reported.  Patients who are taking an antibiotic should separate the dose of the probiotic and antibiotic by at least 2 hours.  Since probiotics contain live bacteria, there is some concern an antibiotic may interfere with the probiotic.  

In conclusion, there is some evidence of probiotics being effective in the treatment of constipation.  In particular, Bifidobacterium lactis was found to have the most benefit in increasing whole gut time and improving the frequency and consistency of the stool.  Should probiotics help, they routinely may need to be used in order to continue to see results.  


Bifidobacteria. Therapeuticresearch February 22, 2018.