Aspidosperma pyrifolium (Apocynaceae) is a plant popularly known as "pereiro-de-sertão" and as anothe plants of the genus is known by the production of indole alkaloids. Until now there is no work regardi any kind of cardiovascular activity. The present study evaluated the cardiovascular eeects induced b ethanolic extract of the wood of A. pyrifolium (EEAPW) on spontaneously hypertensive rats (SHR). The wood extract was obtained by maceration in 90%. To the measurement of arterial pressure (AP) and heart (HR), male SHR (250-300g) were anesthetized with thiopental (45 mg/Kg, i.p.) and polyethylene cath were inserted in abdominal aorta and inferior vena cava for recording pressure and to drug administr respectively. Experiments were performed 24 hours after surgical process. The results are presented as m ± standard error. The bolus intravenous administration of EEAPW (0.5, 1, 5, 10, 20 and 30 mg/Kg) produced dose-dependent hypotension (-7.8 ± 1.5%; -9.4 ± 1%; -10.9 ± 1.2%; -15.9 ± 0.9%; -21.2 ± 1.3% and -30.2 ± respectively) and bradycardia (-11.20 ± 1%; -13.74 ± 1.3%; -12.8 ± 1.5%; -12.03 ± 0.8%; -17.37 ± 1.2% and -13.90 ± in non-anesthetized SHR (n=6). The hypotensive response produced by EEAPW remained unaltered afte administration of the nitric oxide synthase (NOS) inhibitor NG-nitro-L-arginine methyl ester (L-NAM mg/Kg, i.v.). The hypotensive response was completely abolished after the administration of the cycloo nase (COX) inhibitor indomethacin, while the bradycardia was attenuated at the doses of 1, 5 and 10 m The obtained results shows that the hypotension produced by EEAPW depends on the endotheli dependent relaxing factors, possibly prostacyclin and that the hypotension induced by EEAPW doe involves the activation of the nitrous oxide (NO) way.