Abstract: This study introduced the clinical experience of Professor PAN Liqun in the treatment of plasma cell mastitis. Professor PAN believes that the treatment should take the understanding of the pathological anatomy as the precondition， take patients' pathogenesis as the basis and combine their menstrual cycles， then expel the toxin through tuofa. At the same time， external therapy should be applied in the treatment， especially the drainage through a small incision following the direction of the breast lesion， which can avoid the massive damage of patients' breast structure particularly the breast ducts， minimize the breast damage and maintain the physical integrity of the breast. Professor PAN's treatment fully plays the academic advantages of the combination of internal and external treatment of traditional Chinese medicine.