Phyllanthus urinaria has a long history of use in traditional medicine systems, particularly in Asia, for the treatment of liver disorders, including hepatitis. However, its relevance for hepatitis is not based solely on tradition; scientific research over the past few decades has investigated its potential efficacy, especially against hepatitis B virus (HBV).

Several in vitro and animal studies have demonstrated that extracts of Phyllanthus urinaria can inhibit HBV DNA polymerase and suppress viral replication. The plant contains a variety of bioactive compounds, such as lignans, flavonoids, and tannins, which are believed to contribute to its antiviral activities. Some clinical studies, mostly small and of variable quality, have reported that Phyllanthus urinaria or related species (e.g., P. amarus) can reduce serum HBV DNA levels and improve some liver function markers in patients with chronic hepatitis B. However, results are inconsistent, with some trials showing no significant benefit over placebo. Systematic reviews and meta-analyses generally conclude that while there is some evidence for efficacy, the quality of the data is limited by methodological flaws and heterogeneity among studies.

In summary, Phyllanthus urinaria is used for hepatitis based on both traditional practice and a growing, though not definitive, body of scientific research. Larger, well-controlled clinical trials are needed to confirm its safety and efficacy.