Today, researchers are working on several promising new treatments to prevent or clear mucus plugs that may leave people with asthma breathing easier.

At the heart of the problem is mucus itself, a viscous mixture of water, cellular debris, salt, lipids and proteins that performs the crucial job of trapping foreign particles and ferrying them out of the lungs. The primary component of this fluid is a family of proteins known as mucins, which give mucus its gel-like thickness. In people with asthma, genetic changes in mucin proteins make the mucus thicker and harder to clear from the lungs.