Sodium hydroxide, also called caustic soda, reacts with skin and hair. This strong base catalyzes the hydrolysis of fats, oils, and proteins. Solutions of sodium hydroxide feel 'slippery' to the touch because, on contact, they hydrolyze fats forming slippery soap. This is very dangerous. Caustic is especially dangerous in the eyes.

Drano^® has sodium hydroxide as its principal active ingredient. Small pieces of aluminum metal are included. The base reacts with the aluminum producing hydrogen gas which brings about a stirring or mixing action.

Although sold as a household chemical, Drano is very dangerous.

Acids also are used to clear clogged drains. SaniFlush^® solid contains hydrogen sulfate salts (bisulfates) that dissolve to produce acid.