Immediate or rapid reduction in blood pressure may be indicated in the management of hypertensive emergencies in patients with recognized cardiovascular or cerebrovascular disease. Our study has shown that pulse administration of diazoxide is effective in reducing blood pressure in these patients with severe, uncontrolled hypertension. Blood pressure reduction was gradual and could be titrated with repeated pulses of 50 or 75 mg of diazoxide. Pulse administration of diazoxide may represent the preferred method of administration in most patients when this potent antipressor agent is indicated. Our experience suggests that pulse diazoxide appears to be a suitable alternative to other parenteral antihypertensive agents and provides a gradual reduction of blood pressure in high-risk patients with severe, uncontrolled hypertension. The procedure carries a minimum risk of serious cardiovascular sequelae.