Potato and carrot are the main sourses of vitamin C and vitamin A each. As a folk ramedy, potato-carrot mixtures have been used to cure a stomach ulcer in Korea. To investigate the effects of carrot juice on the browning of potato juice, we examined the brewing in various ratio of two juices. We also investigated the role of potato juice in the carotene oxidation of carrot juice. Delta "L" values of potato juice were abruptly decreased after 5 min. reaction and they were very different from the juice mixture of potato and carrot. Those containing higher ratio of potato were decreased greatly. In blanching treatment to eliminate the effect of the enzymes in potato and carrot, delta "L" values of cooked potato were decreased a little but those of cooked carrot were decreased greatly. To investigate the fact that the inhibitory effect of carrot juice in potato browning was due to the dilution of polyphenolics of potato juices by carrot juice mixing, we added H20 equivalent to carrot water content to potato juice. The diluted sample showed less decreasing pattern than nondiluted sample. We also added appropriate amount of ${eta}$-carotene to the same samples. Delta "L" values of with added B-carotene were more slowly decreased than those of without added B-carotene.