The aim of the present study was to determine the efficacy of ulinastatin (UTI) for the treatment of sepsis and to investigate the associated molecular mechanisms. Twenty‑four male rabbits were randomly divided into 4 groups, the normal, sham, sepsis model and UTI groups, each containing 6 rabbits. Serum levels of interleukin (IL)‑10 and tumor necrosis factor‑α (TNF‑α) were measured by enzyme‑linked immunosorbent assay (ELISA). Liver, kidney and lung tissues were stained with hematoxylin and eosin (H&E) 36 h after sacrifice and morphological changes were observed under an optical microscope. The expression levels of IL‑10 and TNF‑α proteins in rabbit kidney tissue in each group were determined by immunohistochemical detection and western blot analysis. ELISA results indicated that, compared with the sepsis model, IL‑10 levels were significantly higher in the UTI treatment group (183.91±11.521 pg/ml) at 36 h (P=0.000), while serum TNF‑α concentration decreased significantly in the UTI treatment group (31.637±2.770 pg/ml; P=0.000). Results of western blot analysis were consistent with the immunohistochemistry, indicating that UTI upregulates IL‑10 and downregulates TNF‑α levels. In the current study, UTI was demonstrated to effectively treat urinary sepsis and alleviate the inflammatory response in tissues. These effects were mediated by the upregulation of IL‑10 and downregulation of TNF‑α levels.