In chemistry, to bleach something generally means to whiten it or oxidize it. A bleach is a chemical that exhibits these properties. Common chemical bleaches include sodium hypochlorite, or "chlorine bleach," and "oxygen bleach," which contains hydrogen peroxide. Bleaching can be a preliminary step in the process of dyeing.

Bleach is commonly used as a disinfectant by homemakers and janitors. Bleach should NEVER be mixed with cleaners containing ammonia; the mixture can create toxic gases and volatile explosives.

Other uses:

• Bleach is also a manga by Tite Kubo; see Bleach (manga)
• Bleach is also an album by Nirvana; see Bleach (album)
• Bleach is also a Christian rock group that disbanded in 2004.