1,2-Propanediol is an organic compound with the chemical formula C3H8O2. It is a colorless, viscous liquid under normal conditions, nearly tasteless with a faint sweetness when inhaled, and is miscible with water, ethanol, and various organic solvents. There are two isomers of 1,2-propanediol. Unless otherwise specified, 1,2-propanediol is generally referred to as such.