Platonia insignis Mart. (Clusiaceae) is a medicinal plant from the Brazilian Amazon region. The present study evaluated the biological potential of the ethanol extract (Pi-EtOH) and ethyl acetate fraction (Pi-EtOAc) of the P. insignis fruit shells on the cardiovascular system of rats. Pi-EtOH or Pi-EtOAc (12.5, 25, and 50 mg/kg) was administered intravenously in normotensive rats (260-300 g), and the mean arterial pressure and the heart rate were monitored. The Pi-EtOH induced hypotension ( -11.56 -0.89, -7.43 -0.85, and -17.56 -1.97 mmHg) followed by bradycardia in two highest doses ( -8.89 -3.62 and -15.79 -1.83 beats/min) and Pi-EtOAc, at the same doses, induced hypotension ( -11.2 -1.03, -14.48 -1.13, -29.89 -2.67 mmHg) more intensively, followed by tachycardia at the dose 12.5 and 25 mg/kg (15.64 -2.06, 19.31 -1.92 beats/min) and bradycardia at a dose of 50 mg/kg ( -9.98 -7.33 beats/min). The hypotensive response from Pi-EtOAc was not attenuated when used in the pretreatment with L-NAME, verapamil, propranolol, and hexamethonium. However, when using yohimbine, the hypotensive effect was inhibited ( -4.42 -1.28 (P < .05), -3.29 -0.99 (P < .05), 2.06 -1.18 mmHg (P < .05); Student's t-test). Hence, the Pi-EtOAc seems to act similarly to the a2-adrenergic agonist in this hypotensive effect.