Separation and purification of constituents of the stem bark extract from Alstonia constricta yielded eight alkaloids. Some of these alkaloids had been previously isolated from the root bark of this species (alstonilidine, alstonidine, and 0-3,4,5-trimethoxybenzoyl-quebrachidine), but others (vincamedine, 1-carbomethoxycarboline, and quebrachidine) had not. A new alkaloid, 14-ketoaistonidine [1], is described. © 1987, American Chemical Society. All rights reserved.