BACKGROUND Patients with pemphigus vulgaris may occasionally present the highly active, widespread form of the disease, and/or maybe resistant to conventional oral steroid therapy, and/or manifest significant side effects from the prolonged use of high oral prednisone dosage. Our purpose was to evaluate the efficacy of steroid "pulse" therapy (PT) in these patients. METHODS Eight patients were given alternate-day, one hour, infusions of 8, 9, or 10 mg/kg methylprednisolone Na succinate. Oral prednisone and a second immunosuppressive agent were simultaneously administered; these were rapidly decreased when control of the disease was achieved. RESULTS All patients initially responded well to therapy. The disease recurred in four patients after 3, 4, 9, and 16 months of remission, respectively. Three of these patients were treated again with PT and went into remission. None of the patients who received cyclophosphamide had a recurrence. One patient died of cardiac arrest, 12 days after PT. On a follow-up of 59 +/- 25 months since the last relapse, patients continue in remission. CONCLUSIONS Pulse therapy is recommended as an adjunct to the total management plan of severely affected patients with pemphigus vulgaris. The addition of cyclophosphamide may prevent the disease from recurring. Alternate-day small-quantity bolus infusions over 16-20 days, may be equally effective as the administration of 15 mg/kg/daily for 3-5 days. The risk of cardiac arrest exists even with this, less aggressive form of PT therapy. A medical history of supraventricular arrhythmias may be considered a risk factor.