During the last few years, a relative increase in the number of patients with non-puerperal mastitis was recorded. From 1980 to 1983, 51 patients were treated who were suffering from an abacterially or bacterially complicated nonpuerperal inflammation of the breast tissue. The present paper reports on patients' history, clinical symptoms, and the development of this form of mastitis during different methods of treatment. The importance of pre-existing lesions of the breast tissue and of hormonal data for the pathogenesis is discussed. The authors conclude that the administration of prolactin inhibiting drugs is an effective therapy. This treatment results in lower rates of abscesses. Long-term therapy with bromocryptine can prevent recurrence of this disease.