Bael (Aegle marmelos), also known as Bengal quince or wood apple, has been used traditionally in Ayurvedic and other systems of traditional medicine for a variety of ailments, including digestive issues, diabetes, and kidney conditions such as nephritis. The traditional use mainly stems from the belief that Bael possesses anti-inflammatory, detoxifying, and diuretic properties, which could theoretically support kidney health and alleviate symptoms associated with nephritis (inflammation of the kidneys).

However, scientific validation for Bael's specific efficacy in treating nephritis is limited. While some laboratory and animal studies have indicated that Bael extracts possess antioxidant and anti-inflammatory properties, direct clinical evidence supporting its use for nephritis in humans is lacking. Most references to its use in nephritis are noted in classical Ayurvedic texts or herbal compendia rather than peer-reviewed studies. Thus, the support for Bael's use in nephritis is primarily traditional, and the overall evidence is weak, meriting a low evidence rating.

In summary, Bael's application in nephritis is based on traditional practices rather than robust scientific research. Anyone considering the use of Bael for kidney disorders should consult with a healthcare professional, as there is insufficient scientific data to confirm its safety and effectiveness for this purpose.