Great Plantain (Plantago major) has a long history of traditional use in various cultures for supporting the health of mucus membranes, particularly in the respiratory and digestive tracts. Herbalists have utilized its leaves for centuries as a demulcent—an agent that soothes and protects irritated or inflamed internal tissues. In traditional European and Native American medicine, plantain leaf infusions or poultices were commonly applied to soothe sore throats, coughs, and mouth ulcers, as well as to address gastrointestinal discomforts such as gastritis and mild diarrhea. The mucilage content in the leaves is thought to form a soothing film that can help shield and repair mucus membranes.

While there are some in vitro and animal studies indicating anti-inflammatory, wound healing, and mild antimicrobial properties of Great Plantain, direct clinical evidence in humans for its effectiveness specifically on mucus membrane health is limited. Nevertheless, its continued use in folk medicine and inclusion in herbal preparations for throat and mouth health underscore its reputation as a beneficial herb for supporting mucus membrane integrity. The evidence rating reflects the consistency of traditional use, with moderate but not robust scientific support to date.