English Plantain (Plantago lanceolata) has a long history of traditional use to support the mucus membranes, particularly in the respiratory and digestive tracts. Folk medicine practices in Europe and other regions have utilized plantain leaves as teas, syrups, and poultices to soothe irritated mucous membranes, address coughs, sore throats, and mild bronchial complaints. The mucilaginous (gel-like) compounds found in the leaves are believed to coat and protect irritated tissues, reducing discomfort and inflammation. Additionally, Plantago lanceolata contains bioactive substances such as aucubin, allantoin, and various flavonoids, which are thought to contribute to its soothing and anti-inflammatory effects.

Scientific studies investigating English Plantain’s direct effects on mucus membranes are limited but suggest mild anti-inflammatory and wound-healing properties in vitro and in animal models. However, robust clinical trials in humans are lacking. Most contemporary herbal references continue to recommend plantain as a demulcent and mild anti-inflammatory for the upper respiratory tract, based primarily on historical use and preliminary pharmacological data. Because the bulk of supporting evidence comes from traditional use rather than modern clinical research, the use of English Plantain for mucus membrane support is best considered as "traditional" with moderate evidence (3/5) based on consistency of historical use and plausible mechanisms.