Boerhavia diffusa, commonly known as "Punarnava" in Ayurveda, has a long history of use in traditional Indian medicine. Its primary uses have included support for liver health, diuresis, and anti-inflammatory effects. In the context of anal fistula or fissure, Boerhavia diffusa is sometimes included in multi-herbal formulations, particularly in Ayurvedic practice, with the intention of reducing inflammation, promoting wound healing, and managing discomfort.

However, the evidence for its effectiveness in anal fistula or fissure is largely anecdotal or based on traditional usage rather than rigorous scientific studies. There are no well-controlled clinical trials directly evaluating Boerhavia diffusa as a standalone treatment for anal fistula or fissure. Most of the traditional justification is extrapolated from its documented anti-inflammatory and wound healing properties, observed in preclinical studies or in the context of other conditions. Occasionally, it is used in combination with other herbs in topical or oral preparations for anorectal disorders, but these uses are not backed by high-quality clinical data.

In summary, the use of Boerhavia diffusa for anal fistula or fissure is grounded in traditional practice rather than scientific validation, and the overall strength of evidence supporting this specific use is weak.