Replacing the feeding of green food was studied by adding Vitamin C(Vc) to drinking water for guinea pigs in varied physiological condition.It could meet the needs of Vc in growing and adult guinea pigs that the concentrention of Vc in drinking water was 350 mg/L. In the guinea pigs of varied physiological conditions which included pregnancy and lactating, the concentration of Vc in drinking water should be 700 mg/L.The results show that it is useful to add Vc to drinking water for discontinuing the feeding of green food in guinea pigs.The necessary concentration of Vc in drinking water for late pregnant and lactating guinea pigs is much higher than that of the guinea pigs at other physiological conditions.