Ginseng
Ginseng root is a plant native to the Far Eastern countries of China, Korea, and Japan. It has been used in these cultures for many years as a treatment for many ailments. These include respiratory issues such as mucus buildup in the lungs, sinuses, and throat.
In general, ginseng root is thought to be an expectorant. That means it helps loosen mucus in the body so that it can be expelled from the lungs and throat via coughing or spitting. Specifically, ginseng contains ingredients known as ginsenosides and eleutherosides that have been shown to make the mucus membrane thinner and more flexible so that it can come away from tissues more easily. Ginseng can also help improve breathing by loosening secretions and reducing inflammation in the bronchial tubes.
In conjunction with other treatments, ginseng root may be helpful for those who have asthma or other conditions with thick phlegm.