In a prospective controlled trial 91 consecutive women with eclampsia were randomly allocated either to a magnesium sulphate and nifedipine regime or to a lytic cocktail and nifedipine group. The type and severity of disease, details of labour and delivery, and the maternal and perinatal outcomes and complications related to the 2 treatment regimens were compared. Recurrence of fits, aspiration pneumonia and sudden hypotension were significantly reduced when patients were treated with the new magnesium sulphate and nifedipine regimen compared with the lytic cocktail plus nifedipine regimen. No patient treated with the new regimen died or had respiratory depression; in the other group there were 2 maternal deaths plus 1 case of severe hypoxic brain damage. No difference was observed in duration of labour or mode of delivery. Perinatal mortality was significantly lower in the magnesium sulphate plus nifedipine treated group. The synergistic action of magnesium sulphate and nifedipine in the dosage employed in this study may be used to reduce maternal and perinatal mortality and morbidity in women with eclampsia.