OBJECTIVE: To study the possible roles of probiotics in decreasing intestinal bacterial colonization rate and the incidence of enterogenic infections in premature infants. METHODS: Seventy premature infants were randomly assigned to two groups: probiotics and conventional treatment groups (control) (n=35 each). The probiotics treatment group was administered with oral Clostridium butyricum powder (250 mg, twice daily up to discharge) 24 hrs after birth except conventional treatment. Rectal swab cultures were done at admission, 5 and 12 days after admission, and before discharge. Clinical and laboratory findings were compared between the two groups. RESULTS: The intestinal bacterial colonization rate in the probiotics treatment group was lower than that in the control group 12 days after admission (60% vs 83%; P<0.05) and before discharge (51% vs 80%; P<0.05). Klebsiella pneumoniae, Escherichia coli and Enterococcus faecium were common colonization bacteria in the two groups. Diarrhea occurred in 7 cases (20%) in the probiotics treatment group compared with 16 cases (46%) in the control group (P<0.05). Two infants (6%) developed sepsis in the probiotics treatment group compared with 9 cases (26%) in the control group (P<0.05). CONCLUSIONS: Probiotics can decrease intestinal bacterial colonization rate and the incidence of diarrhea and sepsis in premature infants.［Chin J Contemp Pediatr, 2010, 12 (3):192-194］