Gallic acid is a naturally occurring trihydroxybenzoic acid found in many plants including tea leaves, grapes, and oak bark. It functions as a potent antioxidant due to its three hydroxyl groups on the benzene ring, enabling free radical scavenging. Used in food preservation, ink production, and pharmaceuticals, it exhibits antimicrobial, anti-inflammatory, and potential anticancer properties. It contributes to plant defense against pathogens and oxidative stress. In humans, it is metabolized to metabolites like 4-O-methylgallic acid and excreted primarily via urine. Its presence in foods contributes to astringency and health-promoting effects from polyphenol-rich diets.