Objective : The purpose of our study was to investigate the effect of JinlnWhaChul-tang-ga-wasong (JIN) on NDEA-induced liver tumorigenesis. Materials and Methods : We investigated the possible protective effects of Jininwhachul-tang-ga-wasong (JIN) as an anticancer against NDEA-induced liver injury in mice. Experimental mice were classified into 3 groups; normal, saline administered group (control group), and JIN extract (0.15g/kg/every other day) administered group (JIN group) after being injected with NDEA over 12 weeks. We examined the state of differentiation of these tumors and the effects of JIN after 6 weeks. To confirm the induction of apoptosis, the cells were analyzed by terminal deorynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay, acridine orange staining and flow cytometric analysis. To investigate inhibitory effect on the expression of COX-2 by JIN, we performed COX-2 immunohistochemistry and reverse transcription polymerase chain reaction analysis. Results : Body weights significantly decreased in the control and JIN groups compared with the normal group. The levels of cholesterol, hemoglobin and testosterone decreased in the control compared with the normal group. The level of estradiol significantly increased in the control compared with the normal group. The control group reacted with TUNEL assay more than the normal and JIN groups. Upon naked eye, light and electron microscopic examination, JIN improved the morphological and histopathological changes of the liver caused by NDEA-induced hepatic neoplasm. COX-2 immunoreactivity decreased in the JIN group compared with the control group, mRNA expression of the control group was greater than the normal and JIN groups. Conclusion : these results suggest the possibility that JIN may exert an anti-tumor effect on NDEA-induced liver tumorigenesis.