Abstract: Objective To study the effect of different dosages of vitamin C on the general condition and immunity level of mice transplanted S₁₈₀ fluid tumor.Methods The model for transplanted S₁₈₀ fluid tumor in mice was set up.The mice were given vitamin C for 7 days and then were killed.The amount of hemog lobin(Hb),the number of white blood cell(WBC),the index of humoral and cellular immunity,the ratio of weight of internal or gans to that of mice body were deter mined.Results Vitamin C had the protective effect on the change of hemogram in tumor-bearing mice and on the damage of immunological organs.But there was not statistical difference.Vitamin C had the evidently protective effect on the immunolo gical function of tumor-bearing mice by using statistical analysis and the degree of this effect depended on dosage.Conclusion Vitamin C can increase the immunological function of tumor-bearing mice,decrease the damage of internal organs in tumor-bearing mice,and can improve the amount of Hb.