Polyporous mushroom, also known as Polyporus umbellatus or Zhu Ling in Traditional Chinese Medicine (TCM), has a long history of use primarily for promoting urination and resolving dampness within the body. In TCM theory, the Spleen is responsible for transforming and transporting fluids, and dysfunction in this organ system can lead to internal dampness and edema. Zhu Ling is traditionally used to support the Spleen by assisting in the removal of dampness, thereby helping to restore balance and proper function. Its use is documented in classic texts such as the "Shennong Bencao Jing" and later materia medica, where it is described as being sweet, bland, and neutral, entering the Spleen and Kidney channels.

While there is some modern pharmacological research suggesting diuretic and immune-modulatory effects of Polyporus umbellatus, direct clinical evidence for its benefits specifically for the Spleen (as understood in TCM) is limited. Most of the support for its use in spleen-related conditions comes from traditional practice rather than rigorous scientific validation. Nevertheless, its longstanding role in herbal formulas targeting Spleen deficiency with dampness provides a moderate level of traditional evidence in favor of its use for this purpose.