Abstract: The intestinal and cardiovascular relaxant activities of a newly synthesized piperidine derivative: 1-(2′, s4′-dimethoxyphenacyl)-4-hydroxy-4-phenylpiperidinium bromide were studied in isolated tissue preparations. The test compound was prepared by dissolving 4-hydroxyphenylpiperidine and 1-(4-methylphenacyl) bromide in acetone. The test compound exhibited dose-dependent relaxant effect on the spontaneous and K+ (75 mM)-induced contractions of isolated rabbit jejunum with respective EC50 values of 0.31 mM (0.09-0.96, 95% CI) and 0.61 mM (0.38-0.99). The Ca++ Channel Blocking (CCB) activity was confirmed when the test compound (0.1-0.5 mM) shifted the Ca++ dose-response curves to the right, similar to that produced by verapamil (0.1-1.0 μM), a standard CCB. When tested in Langendorff perfused rabbit heart preparation, it exhibited a negative chronotropic effect in atria and ventricles with respective EC50 values of 0.28 mM (0.01-8.79) and 0.37 mM (0.01-9.01) and also a negative inotropic effect in atria and ventricles with respective EC50 values of 0.91 mM (0.04-17.69) and 2.77 mM (0.23-32.96). In the isolated rabbit aorta, the test compound showed a dose-dependent vasodilator effect on K+ (75 mM)-induced contractions and norepinephrine (1 μM) peak responses with EC50 values of 0.55 mM (0.24-1.26) and 0.22 mM (0.13-0.38), respectively. The results showed that inhibitory effects of the piperidine derivative on intestinal and cardiovascular preparations are mediated possibly via blockade of voltage and receptor-operated Ca++ channels.