Also called propane-1, 2-diol, is an organic compound with the chemical formula C3H8O2. It is a viscous colorless liquid which is nearly odorless but possesses a faintly sweet taste. Main ingredient of most E-Juices due to its commonplace and cheap cost. PG brings out more of the flavor and throat hit when blended simply and is commonly found at 50% or higher in cheaper E-Juice to enhance flavor while keeping cost low.