Poria mushroom (Poria cocos, also known as Fu Ling in Traditional Chinese Medicine) has a long history of use in East Asian herbal medicine. Traditionally, it is prescribed to "drain dampness," promote urination, and support the spleen. In TCM theory, swollen lymph glands are often interpreted as manifestations of "dampness" or "phlegm" accumulation. As a result, Poria is sometimes included in herbal formulas aimed at addressing swellings, including swollen glands, by promoting fluid metabolism and reducing edema.

However, the direct use of Poria specifically for the treatment or support of swollen lymph glands (lymphadenopathy) is not strongly emphasized in classical texts. Its inclusion for such symptoms is usually as part of complex herbal combinations rather than as a standalone remedy. There is little to no scientific research directly investigating the effect of Poria mushroom on lymphatic tissue or swollen glands in modern biomedical terms. Some laboratory studies suggest that Poria has mild anti-inflammatory and immunomodulatory effects, but these have not been specifically linked to lymph node swelling in clinical settings.

Therefore, the justification for using Poria mushroom for swollen glands comes mainly from traditional practice rather than scientific validation, and the supporting evidence is weak and indirect.