Prunes could exert cardiovascular protective effects. Trials have demonstrated antihypertensive effects of Prunus domestica. The aim of this study was to find out if prunes could alter cardiac functions that may help understanding the mode of control of hypertension. Changes in rate and contractile force of frogs' heart were recorded using Power Lab. Effects of prunes' extracts: aqueous (10, 20, 40%); methanolic, acetonic, ethanolic and chloformic (10%); were evaluated and compared with other drugs. We tested effects of acetylcholine and atropine (10-5), adrenaline, propranolol, verapamil and diltiazem (10-3); NaC1, KCl, CaC1, MgC1 (10% w/v) on frog's heart alone and with prunes/drugs. All extracts of prunes significantly reduced HR and contractile force. Prunes combined with acetylcholine, propranolol or verapamil significantly enhanced bradycardia; whereas it blocked tachycardia produced by epinephrine, atropine or calcium; moreover prunes blocked the significant increase in HR and cardiac contractility produced by CaCl2; and reduced HR along with MgC1. NaCl and KCl alone or with prunes had non-significant effects on frog's heart. In conclusion, Prunus domestica plays a key role in modification of intracellular Ca concentration resulting in negative ionotropic and chronotropic effects (similar to cholinergic stimulation and adrenergic or calcium channel blockade) that could lead to hypotensive effects.