Vasodilator

Vasodilation is a process by which blood vessels in the body become wider following the relaxation of the smooth muscle in the vessel wall. This will reduce blood pressure - since there is more room for the blood.

Vasodilation also occurs in superficial blood vessels of warm-blooded animals when their ambient environment is hot; this process diverts the flow of heated blood to the skin of the animal, where heat can be more easily released into the atmosphere. The opposite physiological process is vasoconstriction.

A vasodilator is a substance that causes vasodilation. Several vasodilators are used as drugs which may, for example, allow blood to flow more easily around a clot.