Cang Er San is used to supplement the wei or protective qi, which defends the body from invasion by external pathogens. To this formula, magnolia flower (xin yi hua), xanthium (cang er zi), and angelica dahurica (bai zhi) have been added to address symptoms of chronic or allergic rhinitis, open the sinuses, relieve sinus headache, and disperse wind and dampness. In addition, red peony (chi shao) and forsythia (lian qiao) have been included. These herbs, according to modern research in China, address allergic inflammation. This formula is extremely effective for airborne or environmental allergies. It both stabilizes the exterior and supplements the qi to strengthen the body’s defenses.
It is an excellent choice for hypertensive patients with allergies or other persons who cannot tolerate formulas that contain ephedra (ma huang).