The latex ofCalotropis gigantea contains caoutchouc to a small extent. 1.3%. The resinols are best separated from the coagulum by means of acetone. The mixture consists essentially of resinols having the formula C30H50O and by repeated fractional crystallisation a very small yield of α-calotropeol could be obtained. The toxic principle of the latex, gigantin, contains nitrogen and sulphur and resembles uscharin in several respects, but differs from it in composition and in its behaviour on hydrolysis.