The effect of ascorbic acid (AsA) or kimchi on the metabolism of xenobiotics in guinea pig administered policyclic aromatic hydrocarbons(PAH) an environmental pollutant was inves-tigated. Guinea pigs given oral supplementation were divided into 4 groups. Group A(control) was supplemented with 2mg of AsA/day group B with 2mg of AsA and PAH/day gruop C with 50mg of AsA and PAH/day. Changes of liver cytochrome P-450 contents and 7-ethoxycou-marin O-deethylase(ECOD) activity glutamate-oxaloacetate transferase(GOT) activity in serum and AsA contents in various tissues were determined. Cytochrome P-450 contents ECOD activity and GOT activity increased in B, C and D groups administered PAH. Moreover cytoch-rome P=450 contents and ECOD activity in group C were higher than those of group A and D. The content of AsA in the tissues of group B was lower than that of A, C and D groups respectively. These results suggested that AsA was necessary in the PAH metabolism moreo-ver supplementation of large amount of AsA or kimchi in the guinea administered PAH had an influence in the drug-metabolizing enzyme induction thus caused a decrease of AsA in tissues.