Cocoa polyphenols comprise a diverse group of flavonoids extracted from Theobroma cacao beans, dominated by monomeric flavan-3-ols such as (-)-epicatechin and (+)-catechin together with oligomeric procyanidins. These compounds impart bitterness and astringency to cocoa products while exhibiting potent antioxidant activity through free-radical scavenging and metal chelation. Research indicates potential cardiovascular benefits via improved endothelial function, reduced LDL oxidation, and anti-inflammatory effects. They are sensitive to heat, oxidation, and alkaline processing, leading to significant losses during chocolate manufacture. Solubility is highest in polar solvents; they contribute to the health-promoting properties of dark chocolate and cocoa extracts used in functional foods.