Four indole alkaloids have been isolated and characterized from the tree bark of Alstonia muelleriana Domin. One of these is the previously known dimeric indole alkaloid, villalstonine (I). A second probably dimeric indole alkaloid, alstonisidine (II), and two monomeric indole alkaloids, alstonisine (III) and alstonerine (IV) are also described. © 1971.