The response of the cardiovascular system to DV-7028 demonstrated the complex action of this substance. In anaesthetized rats DV-7028 decreased the blood pressure and heart rate. These effects did not occur in pithed rats. The hypotensive action and bradycardia was partially reduced in vagotomized animals. DV-7028 potently inhibited the vasoconstrictory effects of serotonin in isolated perfused hindlegs of rat and caused a concentration-dependent shift to the right of response curve to serotonin in the rat tail artery. The present data demonstrate that DV-7028 is a potent 5-HT2 receptor antagonist. Besides its peripheral action, DV-7028 exerts central effects which cause hypotension and bradycardia.