Objective In this study, we tested the therapeutic efficacy and mechanisms of action of Du Zhong injection in a mouse mastitis model. Methods The mastitis mouse model was produced by injection of lipopolysaccharide (LPS) into the breast duct. At 12 h post LPS injection, mice were split into six groups and administered different concentrations of Eucommia ulmoides (Du Zhong) into the abdominal cavity. After a further 12 h recovery, mice were killed and the mammary glands collected. Pathological changes in each group were observed using hematoxylin and eosin staining. Changes in tumour necrosis factor?α(TNF?α), interleukin?6(IL?6) and interleukin?1(IL?1) cytokines in breast tissue were detected by enzyme?linked immunosorbent assay. Results The mouse mastitis model was successfully constructed using 50 μL of 0. 2 mg/ ml LPS. Pathological examination revealed that, increasing doses of Du Zhong injection were associated with decreased mammary gland injury in the model mice, with the greatest effect observed at 20 mg/ kg and 27 mg/ kg. By enzyme?linked immunosorbent assay, Du Zhong injection also reduced pro?inflammatory cytokine expression in the breast tissue, with greatest effects observed at 27 mg/ kg ( P < 0. 01). Conclusions Du Zhong injection can significantly reduce pathological damages, pro?inflammatory cytokine release, and neutrophil invasion in mammary gland tissue in a mouse model of mastitis, with an optimal dosing of 27 mg/ kg.