INTRODUCTION: Different studies indicate that Maytenus has many effects and that M. obtusifolia species has a central nervous system depressant effect. OBJECTIVE: To determine antipsychotic and behavior modifying effect of the Maytenus macrocarpa (Ruiz & Pav.) Briq.ethanolic extract, using the forced swim test and Irwin test. METHOD: 77 albino mice were used, with an average weight of 25 g. They were split into 7 groups and they were administered with Maytenus macrocarpa of 200 mg/kg, 400 mg/kg, 600 mg/kg, 800 mg/kg, 1000 mg/kg, caffeine 32 mg/kg, diazepam 32 mg/ kg, fluoxetine 30 mg/kg, haloperidol 5 mg/kg, distilled water (placebo) 0,1 ml/10 g, and a control group. The Irwin test was used to evaluate presence or absence of lethality, convulsions, Straub tail, sedation, excitement, abnormal gait, jumps, motor in coordination, abdominal writhes, piloerection, stereotypies, head twitches,...