A twining, eastern Mexican vine(Exogonium purga)having tuberous roots that are dried, powdered, and used medicinally as a cathartic.

• 球根牵牛，药喇叭一种墨西哥东部的缠绕藤本植物（外蕊属泻的），其块茎晒干并研成粉末可用作通便药