Petroleum jelly is generally safe to use. Rarely, however, inhaling fat-based substances (lipoids) — such as petroleum jelly or mineral oil — for prolonged periods can cause lung problems.
Typically, petroleum jelly applied to the inside of the nostrils drains down the back of the nose with normal nasal secretions and is swallowed. Rarely, small amounts of the jelly can migrate into the windpipe (trachea) and lungs. Over many months, the jelly can accumulate in the lungs — leading to potentially serious inflammation known as lipoid pneumonia.
In some people, lipoid pneumonia causes no signs or symptoms. In others, lipoid pneumonia may cause cough, chest pain or shortness of breath.
Lipoid pneumonia is often detected on a chest X-ray or computerized tomography (CT) scan. Sometimes, the diagnosis is confirmed with a bronchoscopy.
When lipoid pneumonia is caused by petroleum jelly, generally the only treatment is to stop using the petroleum jelly. To relieve nasal dryness without petroleum jelly, use a vaporizer or humidifier or try over-the-counter saline nasal spray. If you must use a lubricant, choose the water-soluble variety. Use it only sparingly, and not within several hours of lying down.