The effects of sufoxazine on various experimental amnesia models were studied using passive avoidance behavior in mice. Sufoxazine had no influence on learning and memory in intact mice. Sufoxazine, administered either immediately after CO2 exposure or 30 min prior to the acquisition trial, improved CO2 induced amnesia. It also improved both electroconvulsive shock (ECS) induced amnesia (administered immediately after the amnestic treatment) and scopolamine induced amnesia (administered immediately after the acquisition trial). The antidepressant drugs, imipramine and desipramine had no ameliorative activity in any of these experimental amnesia models. Evidently, sufoxazine improves amnesia experimentally induced by various methods.