Gallic Acid Monohydrate (3,4,5-Trihydroxybenzoic acid Monohydrate) is a hydrate of Gallic Acid, a natural polyhydroxyphenol, which inhibits the free radical scavenging effect of COX-2, and possesses a variety of physiological activities such as antioxidant, anti-inflammatory, anti-tumor, and antibacterial.