In this paper we are reporting the results of a study of the distribution of ascorbic acid in the blood in human subjects and in guinea pigs. EXPERIMENTALFifty healthy medical students (47 males and 3 females) on self-selected diets and 50 patients (41 males and 9 fe-. males) in a municipal hospital were studied. Oxalated blood samples were collected under fasting conditions about 15 hours post-prandial. The ascorbic acid con-,.tent of the whole blood and the plasma was determined by the method of Roe and Kuether (1). The concentration of ascorbic acid in oxalated whole blood and plasma was also determined by the same method in guinea pigs upon an apparently adequate diet (2) made up to contain different levels of ascorbic acid. RESULTS