Cancer prevention requires avoidance of tobacco, alcohol, high-fat diet, polluted air and water, sedentary lifestyle, and of mechanical, physical, psychological, or chemical stress. How these factors can cause cancer, is suggested by the transcription nuclear factor-kappa B (NF-κB), that is activated by tobacco, alcohol, high-fat diet, environment pollutants, cancer-causing viruses (human papillomavirus, hepatitis B and C viruses, HIV) and bacteria (Helicobacter pylori), ultraviolet light, ionizing radiation, obesity, and stress. Furthermore, NF-κB–regulated gene products have been implicated in transformation of cells, and in proliferation, survival, invasion, angiogenesis, and metastasis. Suppression of NF-κB activation by the phytochemicals present in fruits and vegetables provides the molecular basis for their ability to prevent cancer. Other agents identified from spices and Ayurvedic and traditional Chinese medicines also been found to suppress NF-κB activation and thus may have potential for cancer prevention. The classic chemopreventive agent should offer long-term safety, low cost, and efficacy. The current review discuses in detail numerous agents such as curcumin, resveratrol, silymarin, catechins and others as potential chemopreventive agents. Thus, cancer, an ancient problem, may have an ancient solution.