Counterirritant

A counterirritant is a substance applied to the skin to produce mild irritation or inflammation in one part of the body in order to relieve pain or inflammation somewhere else in the body. Common counterirritants include capsaicin, menthol, methyl salicylate and camphor, which work by stimulating the skin's sensory receptors rather than by numbing the area, easing pain felt in deeper structures such as joints, muscles and tendons. The United States Food and Drug Administration has noted that the use of these products dates from antiquity, making counterirritation one of the oldest continuously used treatment principles in medicine.