There are 43 species of alstonia trees.  The bark of the tree is used medicinally in the Pacific Rim and India.  Constricta, which is native to Australia, is used extensively as an Aboriginal folk remedy for fever, chronic diarrhea, dysentery and rheumatism.  Scholaris, found growing mostly in India, Pakistan and the Philippines, is used for the same purposes, but may also be employed as a treatment for malaria, and is thought to have aphrodisiac qualities.  In all cases the bark is powdered and made into a tea.  The inner bark of Alstonia constricta is said to possess marked antiperiodic properties, while the outer bark is stated to have been efficacious in curing certain forms of rheumatism. Further trials are needed, however, before it can be ranked as a substitute for quinine, or other of the cinchona alkaloids, yet it has proved as efficient in intermittents.  Scientific investigation has failed to show why it is of such service in malaria, but herbalists consider it superior to quinine and of great use in convalescence .  It lowers fever, relaxes spasms, stimulates lactation and expels intestinal worms.  Used for chronic diarrhea, dysentery and in intermittent fever; also as an anthelmintic. It is also much used by homoeopaths.