Gamma-oryzanol is a naturally occurring component in rice bran and rice germ, which consists of a mixture of ferulic acid esters of sterols and triterpene alcohols. The mechanism of action of gamma-oryzanol is believed to be involved in the metabolism of catecholamine in the hypothalamus. The antioxidant effect of gamma-oryzanol was well documented and excellent in inhibiting lipid peroxidation. Isolation, extraction, and purification of gamma oryzanol were first reported in the mid-1950s. It has been sold in Japan as a medicine since 1962, first to treat anxiety and later in menopause. Gamma oryzanol and rice bran oil therapy have been used to manage elevated cholesterol and triglyceride levels since the late 1980s. No human clinical studies reported adverse effects of rice bran or its fiber fraction.