It was not until the well conducted clinical trials of drugs in the treatment of hypertension (highblood pressure) carried out at the Veterans Administration Hospitals in the United States in the 1950’sthat it became clear that lowering of high blood pressure would lower the possibility of stroke, heartattack, heart failure and kidney damage. At the time the trials were conducted, only a few efficacious antihypertensive drugs were available, namely reserpine, hydralazine and veratrum alkaloids. Sincethe 1950’s, many new classes of efficacious antihypertensive drugs have been introduced and continueto be introduced. Moreover, our knowledge of the biology of the cardiovascular system (heart andblood vessels) continues to increase. The conscientious physician therefore has a responsibility tokeep up with new developments if she/he is to choose the appropriate drug or drugs for their patients.