Ellagic acid is a naturally occurring polyphenol and dilactone of hexahydroxydiphenic acid, abundant in pomegranates, strawberries, raspberries, walnuts, and other plant sources. It forms via hydrolysis of ellagitannins during digestion or food processing. This compound demonstrates strong antioxidant activity by scavenging reactive oxygen species, chelating metal ions, and upregulating endogenous antioxidant enzymes. Research indicates potential anti-inflammatory, anti-proliferative, and chemopreventive effects through modulation of NF-κB, Nrf2, and apoptosis pathways. It is poorly bioavailable but metabolized by gut microbiota into urolithins. Ellagic acid is used in dietary supplements and studied for cardiovascular, metabolic, and anticancer applications.