Poria mushroom (Poria cocos, also known as Fu Ling in Traditional Chinese Medicine) has a long history of use in East Asian herbal medicine, particularly for supporting urinary tract and kidney health. In traditional Chinese medical texts, Poria is described as a diuretic and is believed to "drain dampness" and promote urination. It is commonly included in formulas prescribed for conditions such as edema, difficulty urinating, and urinary tract discomfort, including symptoms that today might be classified as urinary tract infections (UTIs).

Regarding scientific evidence, there are few modern studies directly evaluating Poria's efficacy for UTIs specifically. Some laboratory research suggests Poria may have mild anti-inflammatory and diuretic properties, and it may influence immune function, but clinical trials in humans for UTI prevention or treatment are lacking. The traditional use remains the primary justification for its inclusion in herbal formulas targeting urinary tract complaints. Therefore, while it is widely used for this purpose in traditional practice, especially in Chinese herbal medicine, robust scientific validation for its effectiveness against UTIs is currently insufficient.

In summary, Poria mushroom's use for urinary tract symptoms is based on longstanding tradition rather than strong scientific evidence, warranting a moderate evidence rating of 2.