American Elder (Sambucus canadensis) has a long history of traditional use among Native American and European herbalists, particularly for respiratory conditions such as colds, flu, and sinus congestion. Its flowers and berries have been prepared as teas, syrups, and tinctures for their purported anti-inflammatory and immune-supportive effects. While there is some scientific interest in European elder (Sambucus nigra), most clinical studies focus on its antiviral properties rather than direct effects on allergies or respiratory allergy symptoms.

The rationale for elder's use in allergies comes from its traditional application as a diaphoretic and anti-catarrhal agent, thought to help clear mucus and ease respiratory discomfort. However, there is little to no high-quality clinical research specifically evaluating American Elder's efficacy in treating or alleviating respiratory allergies such as hay fever or allergic rhinitis. The available evidence is mostly anecdotal or based on its generalized use for upper respiratory support, not for allergic mechanisms specifically.

In summary, the use of American Elder for respiratory allergies is based primarily on traditional herbal practices rather than modern scientific validation. Its application persists in folk medicine, but scientific evidence supporting this use remains minimal.