demulcent \dih-MUHL-suhnt, adjective:

1. Soothing or mollifying, as a medicinal substance.

noun:
1. A demulcent substance or agent, often mucilaginous, as for soothing or protecting an irritated mucous membrane.

It will do you no harm to keep close, drink nothing but demulcent barley-water and eat gruel, thin gruel—no beef or mutton, no wine or spirits.
— Patrick O’Brian, Master and Commander

She knew where sour grass grew, which you chew for dyspepsy, and mint, excellent for the nau-shy, and the slippery elm, whose fragrant inner bark was the favorite demulcent of a hundred years ago—the thing to use for raw throat and other sore tishas.
— James Thurber, Writings and Drawings

Demulcent comes from the Latin word dēmulcere which meant “to soften.”