Methyldopa, antihypertensive drugs, alpha agonists, commonly used in tablet form. This product is an exciting vascular movement center of the α -receptor, thereby inhibiting the diplomatic sensory nerve, producing antihypertensive effect, accompanied by slowing down the heart rate, reduce cardiac output, small artery dilation, peripheral vascular resistance significantly reduced, long-term application of cardiac output reduction is not obvious. Clinical use for moderate, severe or malignant hypertension, especially for secondary hypertension, gestational hypertension, heart failure with hypertension, coronary heart disease with hypertension and elderly patients with hypertension.