Five food substances rich in chemopreventive agents were assessed for their potential to increase the activity of endogenous antioxidant enzymes in the liver. The dietary supplements used were, onion, cabbage, honey, green tea and their combination. The effects of these supplements on the activities of catalase (CAT), glutathione-s-transferase (GST), glutathione reductase (GR), cytosolic superoxide dismutase (SOD1) and mitochondrial superoxide dismutase (SOD2) were examined. The result showed that the combination of these products increased the antioxidant enzymes activities significantly (p<0.05) and more potently than individual food supplement compared which animals on normal diet. Supplementation with the individual diet supplement significantly increased the activities of all the enzymes (p<0.05) except SOD1 and SOD2. However, combination of the supplements significantly increased the activities of SOD1 and SOD2 (p<0.05) in addition to the activities of the enzymes increased by individual food supplement (p<0.05)