This review takes a deep look at increases in the incidence of cancer and heart disease after the introduction of industrial vegetable oils in the world. Most vegetable oils are highly processed and refined products, which completely lack the essential nutrients. Omega-6 Linoleic acid from vegetable oils increases oxidative stress in the body of humans, contributing to endothelial dysfunction and heart disease. The consumption of these harmful oils which are high in mega-6 polyunsaturated fats results in changing the structure of cell membrane which contribute to increasing inflammation and the incidence of cancer.