Reserpine is a drug that is used for the treatment of high blood pressure, usually in combination with a thiazide diuretic or vasodilator. Large clinical trials have shown that combined treatment with reserpine plus a thiazide diuretic reduces mortality of people with hypertension. Although the use of reserpine as a solo drug has declined since it was first approved by the FDA in 1955, the combined use of reserpine and a thiazide diuretic or vasodilator is still recommended in patients who do not achieve adequate lowering of blood pressure with first-line drug treatment alone. The reserpine-hydrochlorothiazide combo pill was the 17th most commonly prescribed of the 43 combination antihypertensive pills available In 2012.

The antihypertensive actions of reserpine are largely due to its antinoradrenergic effects, which are a result of its ability to deplete catecholamines (among other monoamine neurotransmitters) from peripheral sympathetic nerve endings. These substances are normally involved in controlling heart rate, force of cardiac contraction and peripheral vascular resistance.

At doses of 0.05 to 0.2 mg per day, reserpine is well tolerated; the most common adverse effect being nasal stuffiness.

Reserpine has also been used for relief of psychotic symptoms. A review found that in persons with schizophrenia, reserpine and chlorpromazine had similar rates of adverse effects, but that reserpine was less effective than chlorpromazine for improving a person's global state.