The effects of chronic polychlorinated biphenyl (PCB) compound toxicity on L-ascorbic acid metabolism in rats have been studied. PCB treatment brought about a depression in the activities of the enzymes L-gluonolactone oxidase and dehydroascorbatase along with an increased tissue levels and urinary excretion of L-ascorbic acid. PCB toxicity drastically disturbed the normal histological pattern of the liver cells and also significantly changed the hepatic lipid composition. L-ascorbic acid supplementation to the toxicated group of animals, although could not prevent the growth retardative effect of PCB, could afford a definite protection against the enzyme activity alterations and histological changes as caused by PCB toxicity.