Phellodendron, also known as Huang Bai in Traditional Chinese Medicine (TCM), is primarily used for its "heat-clearing" and "dampness-drying" properties. Historically, it has been included in herbal formulas to address symptoms associated with "damp-heat" conditions, which can sometimes manifest as respiratory issues, including congestion and sinusitis. In TCM, sinus congestion is often attributed to "heat" or "phlegm-dampness" in the lung or sinus meridians, and Phellodendron is thought to help clear these pathological factors. However, its direct application for sinus congestion is usually as part of a multi-herb formula rather than as a single agent. There is little direct reference in classical texts to Phellodendron being a primary herb for sinus congestion, but it is occasionally included in broader formulas targeting upper respiratory complaints.

From a scientific perspective, there is insufficient clinical evidence to support the use of Phellodendron for sinus congestion. Some laboratory studies have demonstrated that Phellodendron extracts possess anti-inflammatory and antimicrobial activities, which could theoretically contribute to relieving sinus congestion if caused by infection or inflammation. However, these findings have not been substantiated in high-quality human studies specifically focused on sinusitis or congestion. Thus, while the traditional use exists, the evidence base remains weak and largely anecdotal.