Herbal blends labeled as "proprietary" are commonly used in traditional and folk medicine to support the health of mucus membranes, which include the linings of the respiratory, digestive, and urogenital tracts. Ingredients frequently found in these blends—such as slippery elm (Ulmus rubra), marshmallow root (Althaea officinalis), licorice root (Glycyrrhiza glabra), and mullein (Verbascum thapsus)—have a long history of use in various cultures to soothe irritated membranes and promote their function. The traditional rationale is primarily based on the demulcent properties of these herbs, meaning they can coat and soothe mucosal tissue. Scientific evidence supporting the efficacy of these herbal blends as a whole is limited and mostly extrapolated from studies on individual ingredients. Some small studies and laboratory research suggest that mucilaginous herbs like slippery elm and marshmallow root may offer protective effects for mucosal tissues. However, robust clinical trials are lacking, and most evidence remains anecdotal or from historical texts. Regulatory agencies typically recognize these uses as traditional rather than evidence-based. Thus, while the use of proprietary herbal blends for mucus membrane support is justified by longstanding tradition, scientific validation is minimal.