what is petrolatum
petrolatum. a purified mixture of semisolid hydrocarbons obtained from petroleum, used as a base for ointments, protective dressings, and soothing applications to the skin.Called also petroleum jelly.liquid petrolatum see mineral oil.etrolatum. a purified mixture of hydrocarbons obtained from petroleum; used as a base for ointments, protective dressings and soothing applications to the skin. Called also petroleum jelly. Two types of liquid petrolatum are recognized, light and heavy.