Bismuth subgallate is a yellow colored substance that presents as an odorless powder that undergoes discoloration when exposed to sunlight. It is a heavy metal salt of gallic acid that is highly insoluble and poorly absorbed. Possessing protective effects on the gastric mucosa, strong astringent effects, and not as yet elucidated antimicrobial and hemostatic actions, bismuth subgallate is most commonly available as an over-the-counter internal deodorant where it is often employed as the primary active ingredient.