Acute pancreatitis is a common critical disease of the digestive system. Accumulated data showed that overexpression of cyclooxygenase-2 (COX-2) in acute pancreatitis and experimental pancreatitis could be attenuated with COX-2 inhibitors. In recent years, it has been found that timely administration of indomethacin or diclofenac sodium to anus after ERCP can significantly reduce the incidence of AP after ERCP in patients at high risk of AP. The aim of this study was to evaluate the efficacy of rectal indomethacin in reducing the systemic inflammatory response syndrome (SIRS) score in AP patients.

Inclusion Criteria:

(i) either gender aged 18-70 years; (ii) a confirmed diagnosis of AP; (iii) the time interval from the onset of symptoms to admission was no more than 48 h; (iv) written informed consent was obtained from the patients or their legal representatives.

Exclusion Criteria:

(i) pregnancy and breast feeding mother; (ii) severe chronic diseases such as cardiac dysfunction, chronic obstructive pulmonary disease, renal insufficiency, cirrhosis, inflammatory bowel diseases, and malignancies; (iii) peptic ulcer; (iv) pancreatitis due to trauma; (v) drug allergy; (vi) drug abuse and psychosis.