Thirty-seven carriers of hepatitis B virus were treated with a preparation containing the powdered aerial parts of P. amarus (stone breaker), for 30 days. When tested 15-20 days after the end of the treatment, 22 (59%) patients had lost the hepatitis B surface antigen compared with only 1 patient of 23 placebo-treated controls. Some subjects were studied for up to 9 months and in no case did the surface antigen return. Few or no toxic effects resulting from treatment with P. amarus (stone breaker) were observed.

P. amarus [P. niruri], a plant known locally as Bhoomyaamalakee or Taamalakee, is used in Ayurvedic medicine to combat many stomach disorders and diseases of the genito-urinary system, liver and kidney. In clinical trials it has been effective against infective hepatitis, and its extracts have shown hypoglycaemic, antifungal and anticancer (antiviral) activity. The plant is often admixed with different small herbs and medicinally-less-important related species, notably P. urinaria. Studies on the macromorphology, micromorphology, histochemistry and physical properties of the root, stem and leaf revealed diagnostic features that distinguished P. amarus from related species.

The efficacy of an Indian medicinal plant, P. amarus to treat acute viral hepatitis (AVH) was evaluated in parallel with another drug Essentiale (an essential phospholipid extracted from soyabean oil) and compared with a group of patients who were treated symptomatically with vitamins as the control. Serological profile of 93 sporadic AVH cases of the study showed that 25.8% had an acute infection due to hepatitis A virus (HAV), 52.6% suffered due to hepatitis B viral (HBV) infection, while 19.3% of cases were classified as non-A non-B hepatitis (NANB) by exclusion. On follow-up of the patients at the end of treatment period of 4 weeks with each respective drug regimen, it was seen that both P. amarus and Essentiale brought about significant biochemical and clinical normalcy among the HAV infected patients compared with the control group. In acute HBV group, P. amarus-treated patients recovered faster than the Essentiale-treated group and the controls. Essentiale helped the non-A non-B hepatitis patients to resume biochemical normalcy earlier than the other treatments. It was suggested that P. amarus seemed to accelerate the clearance of hepatitis B surface antigen in 86.9% of convalescing AVH-B cases after 3 months time as against 48.0% in the Essentiale treated group and 50% in the controls.