Although endoscopic sclerosis for control of variceal hemorrhage is an old technique, many questions remain about the technique, its applications, and outcomes after use. This report summarizes recent data from animal studies that relate to clinical questions concerning esophageal varix hemorrhage and sclerotherapy. A reproducible canine model of portal hypertension and esophageal varices is described. Three different studies with this model are summarized and discussed including: 1) comparison of methods for endoscopic control of active variceal hemorrhage, 2) comparison of sclerosing agents using canine venous collaterals and 3) efficacy and safety of sclerosing agents in endoscopic sclerotherapy. In our opinion, these data should assist clinicians who are evaluating or planning clinical sclerotherapy trials.