Euryale, particularly the seeds of Euryale ferox (commonly known as fox nut or "Qian Shi" in Traditional Chinese Medicine), has a long history of use in East Asian herbal practices. Traditionally, Euryale is believed to tonify the spleen and kidney, strengthen the body, and aid in the management of various conditions, including edema (fluid retention). In the context of Traditional Chinese Medicine (TCM), edema is often associated with spleen or kidney deficiency and dampness accumulation. Euryale is considered to have a mildly astringent and diuretic effect, which, according to TCM theory, may help reduce swelling and promote the movement of fluids.

However, scientific validation for these effects remains limited. The majority of evidence is based on historical texts, anecdotal reports, and its longstanding use in herbal formulas rather than on rigorous modern clinical studies. Some laboratory studies have suggested that Euryale ferox contains bioactive compounds with antioxidant and anti-inflammatory properties, but direct evidence supporting its efficacy in treating edema is lacking. Therefore, while its use for edema is justified by tradition, the strength of evidence is moderate at best, primarily rooted in historical practice rather than robust scientific research.