Licorice (Glycyrrhiza glabra) has a long history of traditional use for supporting mucous membranes, particularly in the respiratory and digestive tracts. Scientifically, licorice root contains glycyrrhizin and other active compounds that exhibit anti-inflammatory, demulcent (soothing), and mucoprotective effects. Several in vitro and animal studies have shown that glycyrrhizin and its metabolites can increase mucus production and improve the integrity of the mucosal lining, potentially protecting against irritation and ulceration, especially in the gastrointestinal tract. For example, deglycyrrhizinated licorice (DGL) has been studied for its ability to promote healing in peptic ulcers and reduce symptoms of gastritis, with some clinical trials supporting its use as an adjunctive therapy.

In terms of respiratory health, licorice has been used to soothe sore throats and coughs, and laboratory research suggests it may help reduce inflammation and promote repair of the respiratory mucosa. However, most of the clinical evidence remains limited, with relatively small studies or a lack of large, high-quality randomized controlled trials. Safety concerns with long-term use, particularly related to glycyrrhizin content (such as hypertension and hypokalemia), also limit its application. Overall, while there is a scientific rationale and some supporting data for licorice’s use in supporting mucous membrane health, more robust clinical research is needed to confirm its efficacy and safety for this purpose.