Dietary factors are regarded as exerting major influences on cancer development in various organ sites and in Asia there is particular interest in the potential preventive effects of foodstuffs such as soy products and gingseng. The so-called phytoestrogens, like genistein and daidzein in soy, can bind to estrogen receptors and therefore interfere with the action of estrogen itself, a well-established risk factor for breast, ovarian and endometrial cancers. Although not all results are consistent, there is good evidence for protective influence of soy products against all three of these cancers. In addition, there have been many reports of preventive effects in the prostate. With ginseng, whether white or red, the included polyphenol compounds and saponins may play roles in many different organs, although preventive potential is perhaps best documented for gastric cancer. The traditional diets in Eastern Asia may need more emphasis in efforts to combat the growing problem of cancer in this region of the world.