EUPHRASIA, in botany, a genus of the didynamia angiospermia class. The calix is cylindrical, and consists of four segments; and the capsule is oblong and bilocular. There are six species, two of which are natives of Britain, viz. the officinalis, or eye-bright; and the odontites, or red eye-bright. The eye-bright was formerly celebrated as an ophthalmic, but is now totally disregarded.