Also by the systematic name propane-1,2-diol, is an organic compound (a diol alcohol), usually a tasteless, odorless, and colorless clear oily liquid. It is used a moisturizer in medicines, cosmetics, food, toothpaste, mouth wash, and tobacco products. The U.S. Food and Drug Administration (FDA) has determined propylene glycol to be "generally recognized as safe" for use in food, cosmetics, and medicines. Like ethylene glycol, propylene glycol affects the body's chemistry by increasing the amount of acid. Propylene glycol is metabolized into lactic acid, which occurs naturally as muscles are exercised.