The main observed adverse effects of probiotics were sepsis, fungemia and GI ischemia. Generally, critically ill patients in intensive care units, critically sick infants, postoperative and hospitalized patients and patients with immune-compromised complexity were the most at-risk populations. While the overwhelming existing evidence suggests that probiotics are safe, complete consideration of risk-benefit ratio before prescribing is recommended. (Didari T, Solki S, Mozaffari S, Nikfar S, Abdollahi M.A systematic review of the safety of probiotics.Expert Opin Drug Saf. 2014 Feb;13(2):227-39. ).