Digallic acid is a natural polyphenolic that can be produced by hydrolysis of gallotannins. Like other polyphenolic compounds, digallic acid has antioxidant activity that can be cytoprotective. Digallic acid inhibits reverse transcriptases from human immunodeficiency virus (K = 0.58 µM) and murine leukemia virus. It also inhibits calcium-activated chloride channels, blocking the initial agonist-stimulated chloride current.