Abstract: In this study we examined the preventive properties of Rice Bran (RB) and germ on the incidence of azoxymethane induced colon tumorigenesis in Fisher 344 male rats. We also examined the cytotoxic and apoptotic properties of RB using an in vivo model. Tumor incidence (%) in C and RB 5% and RB 10% were 100, 55 and 64, respectively. Tumors/tumor Bearing Rats (TBR) were 3.8, 2 and 1.56 for C, RB 5% and RB 10%, respectively. Tumor size (mm) was larger in control (6.50) than in rats fed RB 5% and RB 10% (1.33 and 0.64). After 12, 24 and 48 h of incubation with RB extracts, LDH (%) release ranged from 2.25-46.79. Present results suggest that feeding RB at 5 and 10% levels significantly (p<0.05) reduced the incidence of AOM induced colon tumors in Fisher 344 male rats. We conclude that the protective effects of RB against colon tumorigenesis may possibly be attributed to the synergistic/additive actions of phytochemicals contained in RB.