This 20 centimes commemorative stamp from the Republic of Rwanda was issued in 1970 to mark the 150th anniversary of the discovery of quinine by Pelletier and Caventou (1820–1970). The design features the Chinchona tree, whose bark was the source of quinine, a groundbreaking treatment for malaria. Illustrated with botanical detail, the stamp highlights both the bark and the flowering plant against a vivid orange background. Designed by J. Van Noten, it emphasizes the vital role of natural medicine and scientific discovery. A key thematic issue for collectors of medical and botanical philately.