Great progress has been made in the fight against disease in many different fields of medicine, especially in the field of natural medicine. Phytoestrogens and related compounds play a major role in the prevention and treatment of cancer. Chemoprevention, a narrative approach for controlling cancer, involves the use of specific natural products or synthetic chemical agents to overturn, repress, or prevent pre-malignancy before the development of invasive cancer. Several natural products confer protective effects against a wide range of cancers; examples include grains, nuts, cereals, spices, fruits, vegetables, beverages, medicinal plants, herbs, and their various phytochemical constituents including phenolics, flavonoids, carotenoids, and nitrogen-containing and organosulfur compounds. Phytoestrogens and related compounds act by different mechanisms that ultimately provide benefit with minimum or no side effects and protect and treat different types of cancer, including liver, lung, colon, breast, prostate, esophagus, oral, intestinal, and many other carcinomas.