For the past 50 years, the main weapons in the war against cancer have been early detection and surgical removal, radiotherapy, chemotherapy, and attempts to develop gene therapy. However, the results so far are less than ideal. One strategy now is to switch from therapeutic approaches to prevention of cancer by improving lifestyle and by identifying effective natural products as chemopreventive agents. One promising candidate with cancer-preventive effects that are not specific to any organ is Panax ginseng C A Meyer, a herb with a long medicinal history. Its protective influence against cancer has been shown by extensive preclinical and epidemiological studies, but these effects need to be carefully investigated by scientific clinical trials focusing on the major cancer killers -stomach, lung, liver, and colorectal cancer.