Background:  Endoscopic sclerotherapy is widely accepted as an effective treatment for the eradication of esophageal varices in patients with portal hypertension and a history of upper gastrointestinal bleeding. The objective of this study was to assess the effectiveness and safety of absolute ethanol as an alternative sclerosing agent to the commonly used 5% ethanolamine oleate. Methods:  One hundred fifty-seven patients with portal hypertension and a history of variceal bleeding were randomly assigned to sclerotherapy with absolute ethanol (n = 66) or 5% ethanolamine oleate (n = 91) between January 1992 and July 1994. Once eradication was achieved, these patients were prospectively followed until September 1998. Results:  Sclerotherapy with both sclerosants resulted in similar eradication rates (~90%), with comparable numbers of sessions required for eradication (5.4 and 5.9 sessions for absolute ethanol and 5% ethanolamine oleate, respectively). Similar complication and recurrent bleeding rates were observed among both groups. Conclusion:  Sclerotherapy with absolute ethanol is as effective as with 5% ethanolamine oleate in preventing further bleeding in patients with portal hypertension. (Gastrointest Endosc 2000;51:573-6.)