American Elder (Sambucus canadensis) has a longstanding traditional use for treating respiratory congestion, often in the form of elderberry syrups or teas. Its close relative, European elder (Sambucus nigra), has been more extensively studied, but American elder shares similar phytochemical profiles, including flavonoids, anthocyanins, and phenolic acids.

Several small clinical studies and in vitro investigations have demonstrated that elderberry extracts can reduce the duration and severity of cold and flu symptoms, which commonly include nasal congestion. The proposed mechanisms include anti-inflammatory effects, antiviral activity (especially against influenza viruses), and the ability to reduce mucous membrane swelling. A 2016 meta-analysis (Tiralongo et al., 2016) of randomized, controlled trials found elderberry preparations to be effective in reducing upper respiratory symptoms of viral infections, though most studies focused on Sambucus nigra.

While direct scientific evidence for Sambucus canadensis is limited, its chemical similarity to Sambucus nigra suggests comparable effects. Major health authorities acknowledge the potential but call for larger, well-controlled studies to confirm efficacy and safety. In summary, the use of American elder for congestion is supported both by tradition and a moderate level of scientific evidence, primarily extrapolated from studies of its European counterpart.