Diaphoretics (Gr. siaoopelv, to carry through), medicines or agents which promote perspiration. (See Perspiration.) The skin is one of the channels for the discharge of saline substances, and therefore these, particularly the salts of the alkalies, are promoters of the sudoriferous action of the skin. To facilitate their action, the skin should be kept warm and the body in a recumbent position. Bathing with tepid water, as tending to produce exosmose through the glandular membrane, is also favorable. Among the most important diaphoretic saline medicines are tartar emetic, or the double tartrate of antimony and potash, the carbonates of soda, potash, and ammonia, and sulphate of potash, which is one of the constituents of Dover's powder. The tartar emetic is one of the most powerful, and may be used to assist the action of other diaphoretics by producing relaxation, and narcotics may be used for the same purpose. Among vegetable diaphoretics may be mentioned ipecacuanha, another constituent of Dover's powder, guaiacum, and camphor.
It must not be forgotten that water, forming as it does nearly the whole of the perspiration, is perhaps the most powerful as well as safest of all diaphoretics, aided as it may be by warmth, exercise, and friction, and that it should nearly always form an important adjunct to the administration of medicinal diaphoretics.