Controlled trials of sclerotherapy for the prevention of the first variceal hemorrhage in cirrhotics have given conflicting results. In the present study, 106 cirrhotics were randomized to sclerotherapy (55 patients) or control group (51 patients). Admission criteria were no history of previous variceal bleeding and the presence of high-risk varices, i.e., a variceal score less than or equal to 0 according to Beppu et al. Sclerotherapy sessions were performed at time zero, 7 days, 30 days, and then monthly until eradication. Follow-up endoscopies were performed at 6-month intervals thereafter. Control patients underwent repeat endoscopy at 6-month intervals. Bleeding episodes were treated by sclerotherapy in both groups, whenever possible. Mean follow-up was 24 months. Analysis of the results was performed by the intention-to-treat method. Variceal bleeding occurred in 19 sclerotherapy patients (34.5%) and in 17 controls (35.4%, P = NS). Overall mortality was 34.5% in sclerotherapy patients and 50% in controls (P = NS). Seven of the 19 sclerotherapy patients (36.8%) and 11 of the 17 controls (64.7%) who bled died of hemorrhage (P less than 0.05, log-linear model). It is concluded that prophylactic sclerotherapy does not reduce the incidence of first variceal bleeding in cirrhotics. However, there seems to be a trend toward a lower bleeding-related mortality in sclerotherapy patients than in controls.