Inhibitory effect of onion juice on the browning of various fruits and vegetables was examined. When fruits and vegetables were ground in the presence of the onion juice, the juice suppressed the browning of butterbur (Petasites japonicus Miq.), burdock (Arctium Lappa L.), eggplant (Solanum melongena L.), potato (Solanum tuberosum L.), sweet potato (Ipomoea batats Poir.), mushroom (Agaricus bisporus Sing.), seed and placenta parts of sweet pepper and bell pepper (Capsicum annuum L.), apple (Malus domestica Mill.), loquat (Eriobotrya japonica Lindl.), plum (Prunus salicina Lindley), cherry (Prunus avium L.), peach (Prunus Persica Batsch) and papaya (Carica Papaya L.). However, the juice did not suppress the browning of shiitake (Lentinus edodes Sing.) and the rind of banana (Musa paradisiaca L.). With cut fruits and vegetables, dipping in the onion juice suppressed significantly the browning of lotus (Nelumbo nucifera Gaertn.) and apple, and partially potato, while it had no effect on burdock. The browning of the rind of banana was reversely promoted by onion juice.