Polygonatum, commonly known as Solomon's Seal, has a long history of use in Traditional Chinese Medicine (TCM) and other traditional systems for supporting kidney health, including conditions like nephritis (inflammation of the kidneys). In TCM, Polygonatum species (notably Polygonatum sibiricum and Polygonatum odoratum) are believed to "nourish the yin," "moisten dryness," and "tonify the kidneys." Historical texts often include Polygonatum as part of multi-herb formulations targeting symptoms associated with nephritis, such as edema, fatigue, and urinary irregularities.

However, scientific validation for its use specifically in nephritis is limited. A few preclinical studies have explored the anti-inflammatory, antioxidant, and immunomodulatory effects of Polygonatum extracts, which could theoretically benefit kidney inflammation. Some animal studies show renoprotective effects in models of kidney injury, but these are preliminary and do not directly address human nephritis. There is a lack of robust clinical trials evaluating the efficacy and safety of Polygonatum for nephritis in humans.

In summary, Polygonatum's use for nephritis is primarily supported by traditional use and theoretical mechanisms, with insufficient scientific evidence to strongly recommend its use for this condition.