Ten patients suffering from amoebic liver abscess were treated with tinidazole (Fasigyn) 800 mg t.d.s. for 5 days. Nine were cured, and 1 patient required further treatment with other drugs. Following this, a double-blind trial was carried out to compare a group of patients treated with tinidazole with a similar group treated with metronidazole. Each series consisted of 14 patients. In the tinidazole series 13 patients were cured and for 1 patient the result of treatment was dubious. All patients in the metronidazole series were cured, but 1 patient admitted to the trial had previously not been cured by metronidazole. It appears that tinidazole and metronidazole are equally efficaceous in the treatment of amoebic liver abscess.