Investigations on the considerable overlap between Epstein-Barr virus associated, early antigen (EBV-EA) inducing compounds and tumor promoters of mouse skin carcinogenesis have been previously reported (1-3). Furthermore, compounds such as glycyrrhetinic acid and retinoic acid, which inhibit EBV-EA induction by tumor promoters, have been shown to act as inhibitors of in vivo tumor promotion (4-6). Koshimizu et al. have reported that oleanolic acid and ursolic acid, isolated from Gledomu hedwaceu L. (Labiatae), inhibited not only in-vitro EBV-EA activation but also in-vivo tumor promotion (7,8). It was also found that most antipromoters cause anti-inflammatory action in animal skin (9,10). We published earlier the isolation and identification of eight triterpenes from the bark of Eupteleu polyandra Sieb. Zucc. (Eupteleaceae) with anti-inflammatory action (11,12).To search for possible antitumor promoters from natural sources, we carried out a primary screening of the triterpenes 1,2, 5,7,9,12,13, and 17 isolated from E. polyandra and their derivatives 3,4,6,8,10,11,14,15, and 16 using their possible inhibitory effects on EBV-EA activation in Raji cells.