A tropical wood used, in the form of an aqueous infusion, to treat diseases or pain of the kidneys (especially kidney stones).
Aqueous infusions of lignum nephriticum were also well known for their changeable colour, which was later explained as fluorescence. Lignum nephriticum was originally the product of a tropical American tree (probably Eysenhardtia polystachya (family Leguminosae (Papilionoideae))), but it may later have been obtained from an Old World species (perhaps Pterocarpus indicus of East and South-East Asia).
Mid 17th century; earliest use found in John Parkinson (1566/7–1650), apothecary and herbalist. From post-classical Latin lignum nephriticum from classical Latin lignum wood + post-classical Latin nephriticum.