Strychnos is a genus of flowering plants, belonging to family Loganiaceae (sometimes Strychnaceae). The genus includes about 190 species of trees and lianas, distributed around the world's tropics.
The Strychnine tree, Strychnos nux-vomica, native to tropical Asia, is the source of the poison strychnine and the homeopathic remedies, nux vomica (from the seed) and Brucea antidysenterica (from the bark).
Strychnos ignatia ("St. Ignatius bean"), is a closely related Asian shrub/tree, and the source of the homeopathic remedies, Ignatia amara (from the seed) and "Upas tieuté" (Strychnos tieute) (from the bark).
The species Strychnos toxifera is one of the 2 plant sources of the poison curare.
Another notable species is Strychnos spinosa (Lam.), commonly known as the Natal orange.
The ripe seeds of Strychnos potatorum,, known as Therran or Nirmal, can be ground and used as a coagulant to purify water; or they may be rubbed against the inside walls of the earthenware water containers.