Abstract. Probiotics are live microbial feed supplements that beneficially affect the recipient by improving intestinal balance. In an updated systematic review, nineteen trials randomizing more than 2800 infants were included. In a meta-analysis of trial data, enteral probiotic supplementation significantly reduced the incidence of severe necrotizing enterocolitis (typical RR 0.35, 95% CI 0.24 to 0.52) and mortality (typical RR 0.55, 95% CI 0.40 to 0.74). There was no evidence of significant reduction of nosocomial sepsis (typical RR 0.89, 95% CI 0.77 to 1.03). The included trials reported no systemic infection with - supplemented probiotics. Recent data in addition to a report by the European Society for Pediatric Gastroenterology (ESPGAN) concluded probiotics could be generally considered safe.