Jalap, in medicine, the root of the Convolvulus Jalappa, L. an exotic species of bindweed.

This root is imported in transverse slices from Xalapa, in South America. The best pieces are compact, hard., weighty; of a dark ofand have, block striated aril is frequently mixed with slices of bryony-root, which, how-ever, may be easily distinguished by their paler colour and porous texture.

Jalap possesses no smell, and leaves very little taste upon the tongue; but, when swallowed, it' affects the throat with a sense of heat, and occasions a plentiful discharge of saliva. It is advanta- geously employed in various disor-ders, but chiefly as a purgative; for which purpose from 15 to 80 grains, and upwards, are taken in powder: its action in general, Is mild, without causing nausea, or geipes except in hot, bilious habits, and hypochondriacal cases : nor should it be indiscriminately given to children and young persons, whole bowels it re axes, and at length destroys the appetite.