A total of 65 children with mild iron deficiency anemia (IDA) were divided into 5 groups, and received 0, 25, 50, 100 and 150 mg/day of vitamin C (VC) respectively every day for 8 weeks. Hemoglobin, serum ferritin, free erythrocyte and hematocrit were determined every week. At a daily average intake of about 30 mg of VC and 7.5 mg of Fe, the results of the study indicate that: (1) VC supplement alone could effectively control children's IDA, and a dose-dependent relationship was observed. (2) 50 mg/day of VC is the most efficient dosage and 6 weeks is the shortest time for an effective therapy. (3) With a diet predominantly comprised of plant foods, it is suggested that appropriate dose of VC should be supplemented for the children during winter and spring in northeastern areas of China.