Medical Dictionary


noun pet·ro·la·tum \ˌpe-trə-ˈlāt-əm, -ˈlät-\

Medical Definition of PETROLATUM

:  a neutral unctuous substance that is practically odorless and tasteless and is insoluble in water, that is obtained from petroleum and differs chemically from paraffin wax in containing unsaturated hydrocarbons or naphthenes as well as alkanes, and that is produced in several forms: as a :  a yellowish to light amber semisolid mass used chiefly as a base for ointments and cosmetics, as a protective dressing, and in lubricating greases—called also petroleum jelly, yellow petrolatum b :  a white or faintly yellowish mass obtained by decolorizing yellow petrolatum and used similarly to it—called also petroleum jelly, white petrolatum, white petroleum jelly
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