AIM--To study the morphology and function of the liver in visceral leishmaniasis (Kala-azar). METHODS--Percutaneous liver biopsy specimens from 18 patients with confirmed visceral leishmaniasis were examined under light and electron microscopy before and after treatment with pentovalent antimony. The tissue was also examined for hepatitis B surface and core antigens using immunoperoxidase staining. Liver function was investigated in nine patients before and after treatment. RESULTS--Specimens before treatment showed Kupffer cells and macrophages colonised by leishmania parasites in 40% of cases. A chronic mononuclear cell infiltrate had affected the portal tracts and lobules. Ballooning degeneration of the hepatocytes, fibrosis of the terminal hepatic venules, and pericellular fibrosis were common findings. The fibrosis was related to Ito cells transforming to fibroblast-like cells. None of the patients had hepatitis B infection. All patients had biochemical evidence of liver dysfunction before treatment. Liver function improved after treatment. CONCLUSION--Visceral leishmaniasis causes morphological and functional disturbance in the liver. Focal fibrosis rather than cirrhosis occurs. The exact aetiology of hepatic damage is unclear but may have an immunological basis.