RESUMEN
A methanol extract of Syzygium guineense bark inhibited intrinsic contractions of rabbit isolated ileum. The inhibition; at bath concentrations of 0.5 - 2.0 mg/ml; was dose-related but non-linear. It produced sustained hypotension in anaesthetized rats. A dose of 5 ug lowered systolic; diastolic and mean blood pressure by 16; 22and 17; respectively below the pre-drug levels. Maximum effect was obtained at a dose of 40 ug when the systolic; diastolic and mean blood pressures fell by 23; 36and 28; respectively below the pre-drug levels. The greater fall in blood pressure was in diastolic than systolic blood pressure. The extract caused a weaker but similar effect to isoprenaline on rabbit isolated heart. While the effect on rabbit isolated ileum supports the folkloric use of the plant as an antispasmodic; further work is required to confirm and categorize the observed pharmacological activities