Punarnava (Boerhavia diffusa) has a long history of use in Ayurvedic medicine, especially for supporting kidney and urinary tract health. The name "Punarnava" itself means "renewal of the body" in Sanskrit, reflecting its traditional use as a rejuvenative herb. It is commonly included in herbal formulations intended for the management of water retention, urinary disorders, and as a general kidney tonic. Ayurvedic texts describe its use for "mutrakrichra" (difficulty in urination), "ashmari" (urinary stones), and as a "mutral" (diuretic).

While there is a solid traditional foundation for its use, modern scientific studies are still limited and primarily preclinical. Some animal studies have shown that extracts of Punarnava may possess diuretic, anti-inflammatory, and nephroprotective properties. For example, studies have indicated that it may help increase urine output and support kidney function in animal models of nephrotoxicity. However, robust clinical trials in humans are lacking, and the evidence is not yet sufficient to fully validate its efficacy by modern scientific standards.

In summary, Punarnava's use for kidney support is well-established in traditional medicine, supported by some preclinical findings, but lacks strong clinical evidence in humans.