Aqueous leaf extraet of Clusia coclensis was applied at a dose of 40 mglkg intravenously to isolated posterior extremities of six normotensive Sprague-Dawley rals and six Spontaneously Hipertensive rats anaesthelÍzed wíth sodium nembutal. The perfusion was done in the abdominal artery using as carrier Krebs bicarbonate ringer at 37°C and keeping constant perfusion pressures of 100 mmHg in normotensive rats and 150 mmHg in hipertensive rats. The venous return was measured in the inferior vena cava. The extract induced a significant reduction of the venous return begining 2 min after application, in both rat types. This may reflect a peripheral vasoconstriction that, in whole organism, would have an hipertensive effec!. Therefore, the mechanism of the alledgedly systemic hipotensive effeet of the aqueous extract of Clusia coclensis leafs resides probably at a central level, probably acting by a reduction of the con" tractibility of the myocardium.Se inyectó extracto acuoso de hojas de Clusía coclensís en dosis de 40 mg/kg por vía endovenosa en el tren posterior aislado de 6 ratas normotensas (SDN) y 6 ratas hipertensas (SHR) . El extracto provocó en ambas cepas de ratas una reducción significativa del retorno venoso. Se concluye que el extracto de Clusía provoca un efecto vasoconstrictor periférico, por lo que el efecto hipotensor y anti-hipertensivo encontrado anteriormente, podría ser atribuido a un efecto directo sobre el miocardio, mediante una disminución en la fuerza de la contracción cardíaca (efecto inotrópico negativo).