Any of various plants identified with Greek ἄλυσσον and formerly reputed to cure hydrophobia. In early use: †any of several hoary plants of the family Lamiaceae (Labiatae), perhaps Marrubium alysson (obsolete). In later use: any of various plants belonging to the genus Alyssum, or to the genus Aurinia which was formerly included in it.

A European weed, Asperugo procumbens (family Boraginaceae), with trailing bristly stems and small blue flowers in the leaf axils.