A review of recent studies of undesirable effects of gold salts is presented. Marrow aplasia is potentially the most serious side effect with a poor prognosis. Its prevalence is undetermined but may have been overestimated. Gold nephropathy and thrombocytopenia although more common usually have a good prognosis. Both can be satisfactorily treated without prolonged morbidity or mortality. Mucocutaneous reactions although more common are rarely of serious importance and need not necessarily prevent completion of a therapeutic course of gold salts. When indicated the side effects of gold salts can be adequately treated by cessation of therapy and use of corticosteroids. The value of chelating agents is desirable.