mineral oil
Meaning of mineral oil: A clear, tasteless liquid distilled from crude oil, used to soften skin and to slide stool through the bowel.
Definition of mineral oil
Mineral oil is a clear, odorless liquid produced by refining petroleum, made up of a mixture of long carbon and hydrogen chains. Grades intended for medical and food use are highly purified. Applied to skin it forms a film that slows water loss, and swallowed it coats stool and the bowel wall so that stool passes more easily.
Is it a mineral?
Not in the dietary sense. A mineral in nutrition means an element such as iron, zinc or calcium. Mineral oil got its name because it comes from the ground rather than from a plant or an animal, at a time when substances were sorted into animal, vegetable and mineral. It supplies no nutrients at all and is not absorbed in any meaningful amount.
How does it work as a laxative?
It belongs to the lubricant group, the smallest of the laxative families. Because it is not absorbed it travels the length of the bowel intact, coating the stool with a waterproof film. That film slows the reabsorption of water back through the bowel wall, so the stool stays softer, and it reduces friction against the wall itself. Nothing is stimulated and no water is drawn in from the body, which distinguishes it from the other classes.
Where else is it used?
| Setting | Purpose |
|---|---|
| Creams and lotions | Slows water loss from the skin surface |
| Baby oil | Mineral oil with fragrance added |
| Ear drops | Softens hardened wax |
| Manufacturing | Food-grade lubricant for machinery |
What problems are recognized?
The important one concerns the lungs. Because it is bland and oily it triggers little coughing, so a small amount inhaled can slip into the airways unnoticed and settle in the lung, where it provokes a slow, persistent inflammation called lipoid pneumonia. That risk falls on people who swallow with difficulty and on the very young and very old. Leakage past the anal sphincter is common and staining. Prolonged use dissolves the fat-soluble vitamins A, D, E and K into the oil and carries them out. Like petroleum jelly, mineral oil comes from the same refining process; the difference is consistency, with one a free-flowing liquid and the other a semi-solid jelly.
Also known as
Used in a sentence
The chart recorded that mineral oil had been used as a lubricant laxative for several weeks.
Good to know
Despite the name, mineral oil contains no dietary mineral, and inhaling even a small amount can produce a lasting lung inflammation known as lipoid pneumonia.