In this present cardioprotective activity study the crude powder of the Hyoscyamus niger Linn is administered to the male albino rats at the dose of 100mg/100g.b.wt. The markers of cardiac function test assess the normal functioning of heart. If there is a change in their normal values of these makers it indicates the dysfunction of heart. Biochemical parameters like TGL, Ck-MB and LPO were carried out to assess the cardioprotective effect of Hyoscyamus niger Linn crude powder in isoproterenol induced experimental animals. Thus, Plant based drugs have been used worldwide in traditional medicines especially Siddha medicines; suggest various herbal and herbomineral drugs for the treatment of various kinds of cardiovascular diseases. CVD will be the paramount cause of death in India which includes high blood pressure, chronic heart diseases, stroke and congestive heart failure. In the last few decades there has been an exponential growth in the field of Siddha herbal medicines or Tamil medicine.