Vitamin C and the anti-obesity effect of fenfluramine. Increasing doses of fenfluramine were given to female guinea-pigs on a scorbutogenic diet with or without Ascorbic Acid (AA) supplementation. AA alone increased weight and appetite, hepatic and plasma AA. AA deficiency reduced weight after an initial rise. 10 mg/kg fenfluramine in association with the diet produced a gain in weight. Larger doses caused weight loss and reduced appetite. These effects were prevented by AA supplementation. Fenfluramine reduced hepatic and plasma AA significantly in comparison with the animals receiving the diet alone, or the diet with AA supplementation in the absence of fenfluramine administration. It is concluded that AA release plays an important role in the anti-obesity and anorectic actions of fenfluramine. Published in International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin- und Ernahrungsforschung. Journal international de vitaminologie et de nutrition (1979)