Objective:To study the behavioral effects of semi purified fraction prepared from the stem bark of Erythrina ve-lutina on mice.Methods:Three chloroformic fractions (CA)at 50 or 100 mg/kg (CA1,CA2 and CA3)were tested in two behavioral tests:plus maze and open field.Results:In the plus maze test,it was observed a de-crease in the number of entries in the closed arms (NECA)CA2 at both doses as compared to the control group.In the open field test,CA2 and CA3 fractions decreased the number of squares crossed and the time of permanence on the bar,increased the number of falls at both doses in the rota rod test.The CA2 fraction de-creased the NECA,but this data did not characterize an anxiolytic effect.It was the consequence from de-crease of locomotor activity (LA)observed in the open field test,that the decrease of LA and rearing,the number of falls and the decrease in time of permanence on the bar in rota rod test were observed after treatment with CA2 and CA3 at both doses,suggesting sedative effect.Conclusion:The present work demonstrated that CA2 and CA3 fractions have impairing effect on LA and motor coordination.