Dimethylbenzanthracene, a polycyclic aromatic hydrocarbon, is a carcinogen. It interacts with DNA of the living cell through intercalation and alkylation. Thus it plays an important role in the initiation stage of carcinogenesis. Its activity with DNA can activate protooncogenes and inactive tumor suppressor genes. With dimethylbenzanthracene as an initiator and croton oil as a promoter, 100 percent of the experimental animals developed tumors within two weeks. Croton oil has phorbal esters which are well-known inducers of the promotion stage of carcinogenesis. The development of tumors was inhibited completely when coconut oil or trilaurin was applied with croton oil after initiation with dimethylbenzanthracene on the shaved skin of experimental mice. Trilaurin is the most predominant triacyl glycerol in coconut oil. Tripalmitin, another saturated fatty acyl glycerol in coconut oil, reduced significantly the development of tumors in experimental mice