Saccharomyces cerevisiae is a common colonizer of the human gastrointestinal system as a benign organism. Enteral supplementation of this yeast as a probiotic product is effective in the treatment of antibiotic associated diarrhae. In rare occasions it can cause invasive infections. We present two fungemia cases in an intensive care unit following probiotic treatment containing S. boulardii. We are warning the safety of probiotic treatment in critically ill patients. (C) 2017 Elsevier Masson SAS. All rights reserved.