Licorice root (Glycyrrhiza glabra) has a long history of use in traditional medicine systems, particularly in Traditional Chinese Medicine (TCM) and Ayurveda, for supporting respiratory health. In TCM, licorice root (known as "Gan Cao") is often included in formulas aimed at soothing the throat, reducing cough, and clearing phlegm. Its demulcent properties are believed to coat and soothe irritated mucous membranes of the respiratory tract. Furthermore, licorice is considered to have anti-inflammatory and expectorant qualities, which are thought to help with conditions such as sore throat, bronchitis, and cough.

Scientific evidence supporting these uses is moderate. Some in vitro and animal studies suggest that glycyrrhizin and other compounds in licorice root exhibit anti-inflammatory, antiviral, and antimicrobial effects, which could theoretically benefit respiratory health. Small clinical studies have evaluated licorice-containing herbal formulas for respiratory symptoms, but isolating the effects of licorice root alone is challenging due to the multi-ingredient nature of these products. Direct, high-quality clinical trials on licorice root for lung support in humans are limited.

In summary, licorice root’s use for supporting the lungs is primarily traditional, with some preliminary scientific evidence but lacking robust clinical validation. Caution is advised with chronic or high-dose use due to potential side effects such as hypertension and hypokalemia.