It has been suggested that herbs of the Phyllanthus family may have antiviral activity. We therefore tested the effects of three different Phyllanthus extracts on the serologic status of 123 patients with chronic hepatitis B. Eleven patients received an extract of Phyllanthus amarus (L) provided by S.P. Thyagarajan, Madras, India. Forty-two patients received Phyllanthus niruri (L), gathered from Hainan Province in China, and 35 patients received an extract of Phyllanthus urinaria (L), which had been gathered in Henan Province. Thirty-five control patients received no herbal therapy. The patients receiving Phyllanthus urinaria (L) were both more likely to lose detectable hepatitis B e-antigen from their serum and more likely to seroconvert hepatitis B e-antibody status from negative to positive than were patients given either of the other two preparations. No patient changed status with respect to hepatitis B s-antigen.