Left ventricular hypertrophy is a major risk factor for cardiovascular morbidity and mortality. Angiotensin-converting enzyme inhibitors, calcium antagonists, and beta-blockers prevent, and cause regression of, left ventricular hypertrophy after short-term therapy. The ability of diuretics to do the same is unclear. We have performed a meta-analysis of studies documenting the effect on left ventricular mass of 6 months' treatment with 2.5 mg indapamide daily. Six studies comprising 197 patients, aged 20-75 years, were included. There was an overall mean reduction in left ventricular mass index of 13.3%, which was principally due to a reduction in left ventricular wall thickness rather than internal diameter.