Eclampsia is a leading cause of maternal mortality. The prevention of seizure activity in pre-eclampsia and recurrent seizures in eclamptic patients is an essential aspect of management. Many drugs with anticonvulsant properties have been used to treat patients with pre-eclampsia and eclampsia. Magnesium sulfate is a significantly better drug than either diazepam or phenytoin for preventing recurrent seizures in eclamptic patients. Magnesium sulfate has diverse cardiovascular and neurological effects and also alters calcium metabolism. Although the drug crosses the placenta and may affect the fetus, these effects are clinically small and fetal morbidity has been shown to be reduced in randomised studies comparing magnesium sulfate to either phenytoin or benzodiazepines. Dosage regimens of magnesium sulfate are empirical. Because adverse effects of this agent are related to toxicity, the establishment of greater efficacy by using higher dosage regimens needs to be tested against a greater risk of adverse effects. The most serious toxicity related to magnesium sulfate use is magnesium sulfate use is neuromuscular blockade that may result in respiratory arrest. Magnesium sulfate is now the drug choice for treating eclamptic patients. However, further studies are required to establish the role of this agent as a prophylactic agent in the prevention of eclampsia.