The environmental and food contaminants, including therapeutic agents (e.g, antibiotics, antihypertensive drugs, etc.) and oestrogenic endocrine disruptors (xenoestrogens or xenobiotic chemicals), which mediate the oestrogens may lead to the development of cancer. Oestrogens and their metabolites are involved in the cancer pathogenesis of breast, uterus, ovary, pituitary gland, testicle, liver, kidney and bone marrow. Xenoestrogens that can cause cancer include polychlorinated biphenyl congeners, pesticides, food-related mycotoxin zearalenone and its derivatives, ultraviolet screen, some metals, fungicides, algicides, oestrogens, retinoids, pyrethroid insecticides, pentachlorophenol, β-hexachlorocyclohexane, etc. Diet has influence on cancer development, and several compounds, either present as dietary components or contaminants or formed during food processing, may play a role in cancer risk. All these can adversely interfere with the physiological functions of oestrogens; mediate the hormonal responses by binding to oestrogen receptors; interact with steroid hormone binding proteins; inhibit oestrogen synthesis; and overall can interact with enzyme systems to modulate the oestrogen metabolism