The objective of this study was to investigate the efficacy of the active ingredient from Cordyceps militaris mushroom on immunization and cancer prevention in cultured cells and rats. the experiment was divided into 2 phases. Of antioxidants in vitro found that The extract of the Cordyceps militaris mushroom extract still constrains antioxidants with an IC50 value of 63?2.1 mgAAE/g extract and when tested for the effect of inhibiting on 2 cancer cell lines, Liver and Colon cancer cell lines with MTT test, the results were found that the crude extracts from the Cordyceps militaris mushroom had the highest rate of inhibiting liver cancer cells at 29.61 ? 1.87% with an IC50 value of 2.329 mg / ml. And the highest rate of inhibition of colon cancer cells at 51.65 ? 4.07% with IC50 at 0.873 mg / ml. Phase 2, Testing for rats. This study was conducted to discover the hepatoprotective. The experimental group was divided into 6 groups: group 1, normal rats, groups 2-6 received CCl4 to induce liver injury, with group 2 force fed with distilled water, groups 3-5 force fed with 12.5, 25 and 50 mg/kg/day for 30 days. Group 6 force fed with 100 mg/ kg Salymarin. The results was showed that Entering the crude extract from the Cordyceps militaris mushroom at 25 mg / kg body weight resulted in the levels of AST, ALT and ALP enzymes similar to those in the control group. The histological evidences of the liver indicate that helping the damaged liver cells return to function similar to normal rat. And resulting in the levels of BUN and Creatinine were not differenced from normal rat. And all the Cordyceps militaris mushroom extracts will increase the rats' hematologicalvalue equal to normal rats at all measured values. And the amount of the extract from Cordyceps militaris mushroom were not affected by the changes in the white blood cell types in rats. The results of this study concluded that the Cordyceps militaris mushroom extract has medicinal efficacy in inhibiting cancer cells. Is an antioxidant Which has medicinal properties helping to liver protective property and it could increase the immunity in rats