Aims Therapeutic hypothermia has shown beneficial effects in sepsis. This study focused on its mechanism. Main methods Sixteen male Sprague-Dawley rats underwent cecal ligation and perforation and subsequently were treated with either hypothermia (HT; body temperature cooled and maintained at 34 °C by ice pad for 10 h; n = 8) or normothermia (NT; n = 8). Three additional rats underwent sham surgery. The body temperatures of the sham-operated and NT groups were maintained at 38 °C with a thermal pad. After the hypothermia treatment, the HT rats were rewarmed for 2 h. The groups were compared for circulating cytokines (IL-6, IL-10), lactate, high mobility group box-1 protein (HMGB1), and lung and intestinal lesions. Animals were observed for 24 h. Key findings Compared with the sham-operated group, the 2 sepsis group rats had significantly higher circulating IL-6, HMGB1, and lactate levels, and tissue injury. In the HT rats, the levels of IL-6, HMGB1, and lactate, the lung wet-to-dry ratio, and lung and intestinal damage were significantly lower than that of the NT group. Circulating IL-10 levels increased significantly after 12 h in the sepsis groups compared with sham animals, while that of the NT and HT groups were comparable. The survival rates of the NT and HT rats were also comparable. Significance Therapeutic hypothermia in a rat model of sepsis was associated with lower levels of circulating IL-6 and HMGB1, and less capillary leakage and tissue edema. These results suggest that mild hypothermia has potential as a therapy in sepsis. [ABSTRACT FROM AUTHOR]