The results of treatment of myasthenia gravis in 12 patients are reported. There were 10 cases with severe generalized form and two cases with moderate generalized form, one of which associated with polymyositis. Seven patients had prior thymectomy and one of them had a thymoma. All the patients were receiving anticholinesterase drugs with poor response or without any response. One patient received a short, intensive course of dexametazone, and other patient used prednisone after a more prolonged dexametazone course. The remaining patients received prednisone, always beginning with high (100 mg) alternate day oral single-doses. This therapy has been maintained for a period thought to be sufficient to suppress the symptoms, as well as to allow remission or an improvement for remaining even when prednisone had been slowly decreased, after a scheduled of one to two years of treatment. In conclusion, 75% of 12 patients with generalized myasthenia gravis showed improvement or complete remission of symptoms during the corticosteroid therapy. There was only a case with thymoma that showed no response to all treatments. Other patient had a polymyositis associated with myasthenia gravis and showed an excellent therapeutic result. Two patients without thymoma showed an initial worsening. To date no important side effect was noted including in the patients treated for a long period.