Chinese Sumac (Rhus chinensis), also known as "Wu Bei Zi" (Galla Chinensis), has a long history of use in Traditional Chinese Medicine (TCM) for various oral and dental conditions, including canker sores (aphthous ulcers). Traditionally, it is valued for its astringent, anti-inflammatory, and antimicrobial properties, which are believed to help reduce pain, swelling, and promote healing of oral ulcers. The galls of Rhus chinensis contain high levels of tannins, which are thought to contribute to these effects by forming a protective layer over mucosal lesions and inhibiting microbial growth.

Scientific studies specifically evaluating the efficacy of Chinese Sumac for canker sores are limited. Some in vitro research has demonstrated antimicrobial activity of Galla Chinensis extracts against oral pathogens and suggested anti-inflammatory effects, but robust clinical trials in humans with canker sores are lacking. Most evidence for its use in this context is derived from traditional practice and historical TCM texts rather than modern, high-quality clinical data. Therefore, while there is some pharmacological basis for its traditional application, scientific validation remains preliminary, and more research is needed to confirm its effectiveness for treating canker sores.