Mineral oil, a clear, colourless, oily liquid that is a by-product of the distillation of petroleum. Mineral oil is used in medicine as a laxative and as an emollient. Given orally, it coats the bowel and softens the stool mass, thus easing the latter’s passage. Mineral oil is completely Not at all. Like petroleum jelly, mineral oil is an effective emollient, which forms an oily layer on the skin that traps water. Thus it is a common ingredient in moisturizers and other skin care products; some people use mineral oil straight from the bottle to treat dry skin. Baby oil is just perfumed mineral oil. Safety Information. Mineral oil is an inert, chemically stable ingredient, with a long history of safe use in common topical applications.FDA permits the use of mineral oil as an active ingredient in some over-the-counter (OTC) drug product categories, including anorectal drugs, skin protectants and ophthalmic moisturizers.