Three novel hydroxylated tung oil (HTO) components with three conjugated double bonds were synthesized by aminolysis of tung oil with diethylolamine, and their cytotoxic effects on five human tumor cell lines were revealed for the first time. Compared with conjugated linolenic acid (CLnA) and conjugated linoleic acid (CLA) which have anti-cancer activity, the carboxyl-free HTO compounds also exhibited a cytotoxic effect against some tumor cell lines.