Some diets have been shown to be correlated with the development and progression of cancer. In contrast, many kinds of foods are expected to prevent the development and progression of cancer. To identify such cancer-preventive food components and elucidate their cancer-preventive functions, we investigated important anti-cancer effects, that is, growth-inhibitory and apoptosis-inducing effects of some food and food components on cancer cells. Among the vegetables studied, bitter gourd was the most effective in inhibiting the growth of HL60 human leukemia cells. Bitter gourd extract induced apoptosis in the cells. The bitter gourd extract also inhibited growth and induced apoptosis in B16 mouse melanoma 4A5 cells, whereas it inhibited the growth of BALBc/3T3 mouse fibroblast cells only to a small extent. Berries are rich sources of the naturally occurring phenolic pigments anthocyanins, which show a potent antioxidant activity. Bilberry ethanol extract strongly inhibited the growth of HL60 and HCT116 human colon carcinoma cells, and also induced apoptosis in HL60 cells but not in HCT116 cells. Of the berry extracts tested, that from bilberry contained the largest amount of phenolic compounds, including anthocyanins, and exhibited the highest DPPH radical-scavenging activity. The anthocyanidins, delphinidin and malvidin, inhibited cell growth and induced apoptosis in HL60 cells. Delphinidin, but not malvidin inhibited the HCT116 cell growth. These effects of food components probably contribute to cancer prevention.