How Long Do Probiotics Take To Work?

How long probiotics take to work depends on the strain of the probiotic, as well as the condition being treated. For instance, the supplementation of Bacillus coagulans showed an improvement in IBS symptoms after 8 weeks¹, while a combination of multiple probiotic species resulted in improved IBS symptoms after 4 weeks². On the other hand, the use of Saccharomyces boulardii in treating diarrhea showed effects within 5 days of sustained use³. For constipation, the use of L. casei showed improvement in symptoms 2-4 weeks into the treatment⁴.


  1. Zhang, T., Zhang, C., Zhang, J., Sun, F., & Duan, L. (2022). Efficacy of probiotics for irritable bowel syndrome: A systematic review and network meta-analysis. Frontiers in Cellular and Infection Microbiology, 12, 859967.
  2. Yoon, H., Park, Y. S., Lee, D. H., Seo, J.-G., Shin, C. M., & Kim, N. (2015). Effect of administering a multi-species probiotic mixture on the changes in fecal microbiota and symptoms of irritable bowel syndrome: A randomized, double-blind, placebo-controlled trial. Journal of Clinical Biochemistry and Nutrition, 57(2), 129–134.
  3. Cottrell, J., Koenig, K., Perfekt, R., Hofmann, R., & For the Loperamide–Simethicone Acute Diarrhoea Study Team. (2015). Comparison of two forms of loperamide–simeticone and a probiotic yeast (Saccharomyces boulardii) in the treatment of acute diarrhoea in adults: A randomised non-inferiority clinical trial. Drugs in R&D, 15(4), 363–373.
  4. Koebnick, C., Wagner, I., Leitzmann, P., Stern, U., & Zunft, H. F. (NaN/NaN/NaN). Probiotic beverage containing lactobacillus casei shirota improves gastrointestinal symptoms in patients with chronic constipation. Canadian Journal of Gastroenterology and Hepatology, 17, 655–659.

On this page