Phellodendron bark, known as "Huang Bai" in Traditional Chinese Medicine (TCM), has a long history of use in East Asian herbal medicine. However, its primary traditional indications are for "heat" and "dampness" conditions, such as infections, diarrhea, urinary tract issues, and certain skin conditions. While Phellodendron bark is sometimes included in complex TCM formulas for its anti-inflammatory and antimicrobial properties, it is not classically used as a primary remedy for lung congestion or respiratory conditions. Some traditional formulas that address respiratory symptoms may include Phellodendron bark, but it is usually for its ability to "clear heat" or address secondary symptoms rather than directly targeting congestion or phlegm in the lungs. There is limited historical precedent for its specific use in treating lung congestion, and major TCM texts do not list it as a principal herb for this indication.

Scientifically, there is minimal evidence to support its use for lung congestion. Most modern research focuses on its active compounds (such as berberine) for antimicrobial, anti-inflammatory, and metabolic effects, rather than direct expectorant or decongestant activity. In summary, the use of Phellodendron bark for lung congestion is supported primarily by limited traditional usage as part of multi-herb formulas, with very little direct scientific validation or strong traditional precedent for this specific condition.