The effect on schedule controlled behavior and toxicity of Atractylis alkaloid was investigated in the pigeons which were trained on a multiple fixed-ratio fixed-interval schedule of food presentation. Atractylis alkaloid decreased the rate of responding during both the fixed-interval and fixed ratio component of the schedule at 10 mg/kg. Further depression occurred at 30 mg/kg. This flat dose-response curve for depression of conditioned behavior was typical of tranquilizers. Conclusively it was suspected that Atractylis alkaloid had major tranquilizing activity.