Sambucus nigra, commonly known as elderberry, has a long history of use in traditional herbal medicine for respiratory tract infections and to support the health of mucus membranes, particularly in the context of colds and influenza. Modern scientific research has provided some validation for these traditional uses, primarily due to the plant’s bioactive compounds, including flavonoids and anthocyanins, which exhibit antioxidant and anti-inflammatory properties.

Several randomized controlled trials have investigated elderberry extract’s effects on upper respiratory tract symptoms. Notably, a 2016 meta-analysis (Hawkins et al., Complement Ther Med) concluded that elderberry supplementation significantly reduced the duration and severity of cold and influenza symptoms. The proposed mechanism involves elderberry’s ability to inhibit viral replication and to modulate inflammatory cytokines, which may help reduce the irritation and overproduction of mucus in respiratory tract infections. While these effects are not direct evidence of support for "mucus membranes" as an anatomical system, the symptomatic relief and modulation of mucosal inflammation suggest a supportive role.

However, most studies focus on symptomatic relief rather than direct impact on the mucus membranes themselves, and more high-quality research is needed to clarify the specific mechanisms. Nevertheless, there is a moderate level of scientific evidence supporting the use of Sambucus nigra for upper respiratory health, which by extension includes the mucus membranes lining these tracts.