A demulcent (derived from the Latin: demulcere "caress") is an agent that forms a soothing film over a mucous membrane, relieving minor pain and inflammation of the membrane. However, they generally help for less than 30 minutes. Demulcents are sometimes referred to as mucoprotective agents.

As an adjective, demulcent often applies to the soothing nature of some medicines, but you can also use it to describe such things as a soothing voice or a soothing demeanor. The noun demulcent is used for a gelatinous or oily substance that is capable of soothing inflamed or abraded mucous membranes and protecting them from further irritation.