This two-part study investigated the topical treatment of vasospasm in the tail arteries of rats. In part A, an epinephrine-induced model of vasospasm was used to study a variety of vasodilating agents with actions on at least five different sites in the contractile mechanism of the vascular smooth-muscle cell. The most effective commercially available agents evaluated in this part of the study appeared to be 20% lidocaine and Thorazine (25 mg/ml). In part B, a model was established in which epinephrine-induced vasoconstriction was found to significantly impair anastomotic patency. Thorazine was shown to improve the patency rate of vessels in this setting, and it was found to be superior to 20% lidocaine in improving anastomotic patency.