A bromine sanitizer. The initials refer to "bromochlorodimethylhydantoin. When BCDMH dissolves in water it produces a solution of Hypobromous Acid and Hypochlorous Acid. The latter breaks down bromamines to regenerate the bromine sanitizer which has been consumed by forming these compounds. Popular in spa baths.

Chemically, " romo hloro ethyl ydantoin", it is a bromine sanitiser. When BCDMH dissolves in water it produces Hypobromous Acid and Hypochlorous Acid.

BCDMH is a chemical disinfectant used for recreational water and drinking water purification. It is a white crystalline compound with a slight bromine and acetone odor and is insoluble in water, but soluble in acetone. BCDMH is an excellent source of both chlorine and bromine as it reacts slowly with water releasing hypochlorous acid and hypobromous acid.