Lubricant jelly is a gelatinous liquid, typically either water or silicone-based, that is used to moisten skin and soften body orifices. Medical professionals often keep it on hand to ease insertion of vaginal speculums, rectal thermometers, and other instruments that must be put into the body. Some jellies can also be used during sexual intercourse to replace or enhance natural lubrication, and women may keep these sorts of products on hand to ease or relieve vaginal dryness.

Doctors and other healthcare professionals frequently stock medical-grade lubricant jelly to ease pain and discomfort during routine health exams. These sorts of jellies are biologically inert, which means that they will not interfere with test results - if a nurse uses the jelly to guide a probe into the body to collect cell samples, for instance, the cells can be tested without worry that they have been tainted or any way altered. Most can also be safely used with latex gloves, which allows for sterile exams.

Lubricant jelly is also popular as a means of preventing soreness and tearing during sexual intercourse. The sensitive genital areas will usually self-lubricate when aroused, but dehydration, stress, hormonal changes, and certain medications like antihistamines can decrease moistness. When this happens, applying a bit of lubricant can make the experience more pleasurable. It is usually applied to the penis, vagina, or anus.