The hemodynamic effects of the water extract of flower of Chrysanthemum indicum Linn. (CIL) and adenosine were examined in anesthetized open-chest dogs by measuring simultaneously and continuously coronary (CBF), vertebral (VBF), renal (RBF) and aortic blood flows (AoF). Intravenous administration of CIL (5-20 mg/kg) as well as adenosine (10-50 micrograms/kg) produced decreases in aortic blood pressure (AoP) and RBF, and increases in AoF, VBF, CBF and left ventricular dP/dt (LVdP/dt). Calculated coronary, vertebral and total peripheral resistances were decreased by CIL or adenosine in a dose-dependent manner. The ratio (1.69 +/- 0.27) of decrease in coronary vascular resistance to that in total peripheral resistance by CIL (10 mg/kg) was apparently smaller than that (4.03 +/- 0.48) by adenosine (10 micrograms/kg). After beta-adrenergic blockade, increases in AoF and LVdP/dt were inhibited, but decreases in AoP and coronary, vertebral and total peripheral resistances and increase in renal vascular resistance were not changed. These results indicate that CIL directly and uniformly produces coronary and systemic vasodilation with renal vasoconstriction, and that adenosine directly produces vasoconstriction in renal vasculature and vasodilation which is more potent in coronary vasculature than in systemic ones.