Four 14 to 19, year old boys are used as subjects in this study. The first part of this study attempts to investigate the vitamin C status of these subjects when they are consuming the ordinary diet served in the college staff dining room. The vitamin C content of the whole meal is determined by the dye titration method for ten days. During the first 2 days, blood samples are taken from finger tips and the plasma analyed for vitamin C by the Farmer and Abt method. 24-hour urine samples are also collected and the vitamin C content determined.After the first 3 days, in addition to the vitamin C in the diet, the subjects are subjected to vitamin C saturation by taking orally 400 mg of vitamin C form orange juice for two days followed by 5 days of 100 mg supplementation of crystalline vitamin C. Plasma vitamin C and 24-hour urinary vitamin C are ag(?) studied. Following this procedure, the subjects are considered ready for experimentation. They are put on an experimental diet similar to their ordinary d(?) but devoid of vitamin C. The vitamin C intake level is controlled. Three lev(?) are tried: 70 mg, 50 mg, and 30 mg daily. Each level is fed for 14 days. The vitamin C of the first seven days is provided by vegetables frequently used (?) Canton and crystalline vitamin C is used during the latter 7 days for comparison. Cantonese cabbage(Brassica chinensis L.), Kan Lan Tsai(Brassica alboclabia, R.) and Chinese celery cabbage(Brassica pekinensis, R.)are used for supplying vitamin C during the 70, 50 and 30 mg levels respectively. Plasma vitamin C and 24-hour urinary excretion are determined for the last 5 days of each period.The vitamin C content of the medical college diet averages 43.7 mg per day for the 10 days analyzed. Plasma vitamin C of the subjects ranges from 0.25 to 0.61 mg percent, averaging 0.37 mg percent. 24-hour urinary excretion varies between 3.3 and 74.8 mg daily.During saturation, plasma vitamin C of one subject increases after the first dose, while its content in the plasma of the other three subjects also shows gradual rise. Urinary excretions show immediate and considerable increases on the first day with each of the subjects.During the 70 mg vitamin C daily intake level, plasma vitamin C average 0.45 mg percent and 0.48 mg percent for Brassica chinensis, L. and for crystalline vitamin C respectively. Daily urinary excretions average 19.4 and 18.4 mg. for the two periods. When the vitamin C intake is reduced to 50 mg daily, an average of 0.40 mg percent of plasma ascorbic acid is found for Brassica alboclabia, L. and 0.32 mg percent for crystalline vitamin C. Urinary excretion decreases to 15.2 and 11.9 mg daily. At the 30 mg daily intake level, plasma vitamin C falls to 0.32 mg percent for Chinese celery cabbage and 0.31 mg percent for crystalline vitamin C. Total urinary vitamin C falls to 9.9 and 9.0 mg.The vitamin C from these 3 vegetables are at least as efficiently utilized as crystalline vitamin C.While it is not quite possible to draw definite conclusions in regard to vitamin C requirement of these subjects from the results of this study, there are suggestions however that a daily intake of about 50 mg of vitamin C may be able to maintain a fairly satisfactory state of vitamin C nutrition.