We want to enroll 20 BA patients aged 0 to 3 years, who had a Kasai operation. Ten patients are treated with neomycin (25 mg/kg/d, qid, 4 days a week). Another 10 patients receive Lactobacillus casei rhamnosus, Lcr 35 (8x108 CFU/day, bid) The duration of treatment is 6 months. Bacterial cultures of stool are performed before treatment and 1 month, 3 months and 6 months after treatment to evaluate the change of intestinal flora. Another 10 BA patients, from 1991 to 1996, aged 0 to 3 years, without prophylaxis after portoenterostomy, were served as the historical control group. Comparisons of the episodes of cholangitis, time to the first episode, and body weight change are made among the three groups.