Yellow root, commonly referring to Hydrastis canadensis (goldenseal), has a history of traditional use in North American herbal medicine, particularly among Indigenous peoples and later among European settlers. Traditionally, yellow root has been used for a variety of ailments, including as a remedy for respiratory congestion such as bronchitis and other bronchial conditions. The roots contain the alkaloid berberine, which exhibits antimicrobial and anti-inflammatory properties in laboratory studies. Historically, herbalists recommended yellow root infusions or tinctures to help “clear phlegm” and soothe irritated mucous membranes in the upper respiratory tract.

However, scientific research specifically validating the use of yellow root for bronchial congestion is limited. While berberine and related compounds can inhibit the growth of certain bacteria and reduce inflammation in vitro, there is a lack of robust clinical trials demonstrating efficacy in relieving congestion or treating bronchial conditions in humans. Most of the evidence supporting its use for bronchial congestion remains anecdotal and rooted in traditional medicine rather than modern clinical science. Therefore, while yellow root has a clear traditional basis for use in respiratory congestion, scientific evidence supporting its effectiveness is not strong, meriting a rating of 2 out of 5.