What is "bismuth subgallate"

Bismuth subgallate, with a chemical formula CHBiO, is commonly used to treat malodor by deodorizing flatulence and stools. In the United States it is the active ingredient in Devrom (internal deodorant), an over-the-counter FDA-approved medicine. Also, it has been used to treat Helicobacter pylori infection and is used in wound therapy. As an internal deodorant, it is commonly used by individuals who have had gastrointestinal stoma surgery, bariatric surgery, fecal incontinence, and irritable bowel syndrome.

Also, a double blind study in 1974 reported its effectiveness as a flatulence/stool deodorant in ileostomy patients.