Polygonum species, such as Polygonum cuspidatum (Japanese knotweed) and Polygonum multiflorum (He Shou Wu), have a long history of use in traditional Chinese medicine (TCM) for supporting liver health and treating hepatitis. In TCM, these herbs are believed to "clear heat," "eliminate toxins," and nourish the liver. Herbal formulas containing Polygonum are sometimes prescribed for symptoms consistent with hepatitis, such as jaundice and elevated liver enzymes.

Scientific validation for these traditional uses is limited. Preliminary in vitro and animal studies have suggested that certain constituents—such as resveratrol and emodin in P. cuspidatum—may exhibit hepatoprotective, anti-inflammatory, and antiviral effects. However, robust human clinical trials are lacking, and the available research is not sufficient to conclusively support the use of Polygonum species as a treatment for hepatitis in modern medicine. Major pharmacopoeias and clinical guidelines do not endorse Polygonum for hepatitis, and safety concerns (especially regarding P. multiflorum, which can cause hepatotoxicity in some individuals) further limit its use.

In summary, the use of Polygonum for hepatitis is justified primarily by historical and traditional practice rather than by strong scientific evidence.