The latex ofCalotropis gigantea contains (1) resinols as esters of steamvolatile fatty acids (acetic and isovaleric), (2) cardiac poisons similar to usharin and (3) calcium oxalate. The resinol portion consists mainly of two new alcohols, α-calotropeol and β-calotropeol in almost equal quantities and minor amounts of β-amyrin. The important properties of the calotropeols have been studied. It is suggested that ‘Calosterol’ of Basu and Nath should be a mixture of resinols contaminated with cardiac poisons. The recent report of Hesseet al. that the milky latex ofCalotropis procera contains only α-lactucerol as its esters with steam-volatile fatty acids is discussed.