Poria mushroom (Poria cocos, also known as Fu Ling in traditional Chinese medicine) is primarily used based on traditional evidence to support the treatment of swollen lymph nodes or glands. In traditional Chinese medicine (TCM), Poria is classified as a diuretic and is thought to "drain dampness," promote urination, and strengthen the spleen. Swelling of lymph nodes or glands is often interpreted in TCM as a manifestation of "dampness" or "phlegm" accumulation, so formulas for these conditions sometimes include Poria as an adjunctive ingredient to help resolve fluid retention and support the body's fluid metabolism.

However, there is minimal direct scientific evidence supporting Poria's specific efficacy for swollen lymph nodes or glands. Most available pharmacological research focuses on the mushroom’s immune-modulating, anti-inflammatory, and diuretic effects in vitro or in animal models, but these studies do not directly address lymphadenopathy or glandular swelling in humans. Moreover, no high-quality clinical trials have established its benefits for this indication. Therefore, while its use for swollen glands is justified within the framework of TCM tradition, scientific support for this specific application is weak.