Mostuea is one of only three genera of flowering plants belonging to the small family Gelsemiaceae (the other two being Gelsemium and Pteleocarpa). Mostuea and Gelsemium were formerly placed in the family Loganiaceae, while Pteleocarpa was placed variously in the families Icacinaceae, Cardiopteridaceae, Boraginaceae, and others, before the description of the Gelsemiaceae was altered formally to accommodate it in 2014. Mostuea is native to Africa and South America. Anecdotal evidence suggests that the roots of certain Mostuea species are used as ritual aphrodisiacs and entheogens in West Tropical Africa.