ointment
Meaning of ointment: The same drug at the same strength acts more strongly here than in a cream, because sealing the skin lets more of it through.
Definition of ointment
An ointment is a semisolid preparation for the skin built on a greasy, largely water-free base such as petrolatum or a blend of oils and waxes. It may carry an active drug or none at all. Spread thinly it forms a sealing film that holds moisture in the skin, which softens the surface and helps any drug it contains pass through.
How is it different from a cream?
By how much water the base holds. An ointment is nearly all oil, a cream is a blend of oil and water, and a lotion holds still more water and pours. That single difference decides almost everything else about how a preparation feels, where it can be used and how strongly it acts.
| Form | Base | Feel and behavior |
|---|---|---|
| Ointment | Oil, little or no water | Greasy, sealing, stays put, hard to wash off |
| Cream | Oil and water mixed | Rubs in white, less greasy, needs preservative |
| Lotion | Mostly water | Pours, cools, spreads over large areas |
| Gel | Water or alcohol thickened | Dries clear, suits scalp and hairy skin |
| Paste | Ointment plus powder | Stiff, protective, stays exactly where placed |
Why does the base matter so much?
Because it is not inert. Sealing the surface stops water evaporating from the skin, and the trapped moisture both softens hardened plaque and loosens the barrier, so more of any drug crosses into the tissue. The same steroid at the same strength therefore acts more powerfully in an ointment than in a cream. A water-free base also gives bacteria and fungi nothing to grow in, so ointments need no preservative, which removes a common cause of allergic reaction to a topical product. Simple bases with nothing added, such as a petrolatum, mineral oil, lanolin and ceresin ointment, are used as treatments in their own right for dry and cracked skin.
Where does an ointment work badly?
On weeping or blistered skin, where grease traps fluid rather than letting it dry. On hairy skin, where it clumps and mats. In warm folds such as the groin or under the breast, where sealing in heat and sweat can bring on blocked follicles or a heat rash. It stains clothing and bedding, and in the eye it blurs vision until it clears. Preparations such as a polyphenon E ointment illustrate the other side of the choice, since an active drug is often formulated this way precisely because the base keeps it in contact with the skin for hours.
Also known as
Used in a sentence
A thin layer of the ointment was applied to the affected area.
Good to know
An ointment base contains almost no water, so it needs no preservative and resists washing off, but the same sealing effect traps heat and sweat and makes it a poor match for hairy skin, body folds and weeping surfaces.
Word origin
Where “ointment” comes from
Ointment reaches English through Old French from Latin unguentum, a salve, built on unguere, to anoint; the older synonym unguent comes from the same root.