Abstract： Objective： This study observed the effects of Chaiqin Xiaoyong Decoction on the PPAR-γ/NF-κB signaling pathway and macrophages in breast tissue of patients with granulomatous lobular mastitis （GLM） of heat accumulation in the liver meridian type，and explored the mechanism by which Chaiqin Xiaoyong Decoction treats GLM during the mass-forming stage of this type. Methods：Before and after treatment，breast-lesion tissue specimens were obtained by biopsy or surgery from six patients with mass-stage GLM of heat accumulation in the liver meridian type； these samples served as the disease group and treatment group. Six healthy breast tissues from patients without inflammation or malignancy were matched as healthy controls. The HE staining was used to observe histopathological morphology. Immunohistochemistry was performed to evaluate CD68-labelled macrophages. Double immunofluorescence was employed to identify M1 macrophages （F4/80 and iNOS） and M2 macrophages （F4/80 and CD206） within the tissue. Western blot was applied to measure the expression of inflammatory cytokines including tumor necrosis factor- α （TNF-α），interleukin （IL）-1β and IL-6；changes in PPAR-γ/NF-κB pathway-related proteins were detected， and M1-specific markers （iNOS and COX2） as well as M2-specific markers （IL-4 and IL-10） were quantified. Results： Chaiqin Xiaoyong Decoction alleviated inflammatory pathology， reduced TNF- α， IL-6 and IL-1β expression，up-regulated expression of PPAR-γ protein and down-regulated expression of NF-κB p65 protein in GLM lesions，and significantly decreased total macrophage infiltration. GLM tissue in the mass stage showed high expression of M1 markers iNOS and COX2 and low expression of M2 markers IL-4 and IL-10. After intervention with Chaiqin Xiaoyong Decoction，M1 marker iNOS expression was decreased while the distribution and expression of the M2 marker CD206 were increased. Conclusion： Chaiqin Xiaoyong Decoction can alleviate local inflammatory factor expression， reduce macrophage infiltration，and promote the switch of macrophages from the M1 to the M2 phenotype by regulating the PPAR-γ/NF-κB signaling pathway，thereby exerting its therapeutic effect on GLM.