Two isomeric alkaloids, 11-hydroxycephalotaxine and drupacine, have been isolated from Cephalotarus harringtonia var. drupacea (Sieb. + Zucc.) Koidzumi. Evidence is presented to show that these alkaloids are represented by structures la and 2a, respectively. Close proximity of the two hydroxyl functions of la leads to some unusual reaction products. Nearly quantitative conversion of la to ketal 2a occurs under mild acidic conditions. Treatment of la with tosyl chloride in pyridine affords cyclic ether 5, and oxidation of la under modified Oppenauer conditions results in formation of hemiketal 7. The diacetate of la is epimerized under extraordinarily mild conditions.