Abstract: Objective To analyze the efficacy of different administration timing of somatostatin in the treatment of acute pancreatitis and plasma diamine oxidase activity. 
Methods A total of 96 patients with acute pancreatitis treated in Department of Emergency, Beijing Friendship Hospital, Capital Medical University were selected as observation subjects. Of them, 54 patients with mild and moderate disease were divided into group A （＜24 h） and group B （≥24 h） according to whether the administration time of somatostatin was greater than 24 h, and 42 patients with severe disease were divided into group C （＜24 h） and group D （≥24 h） according to whether the administration time of somatostatin was greater than 24 h. The impact of different administration timing on clinical efficacy was analyzed retrospectively. 
Results The total clinical efficacy of group A was 96.30%, which was higher than that of group B, and the total clinical efficacy of group C was 85.71%, which was higher than that of group D (P＜0.05). The remission time of abdominal pain and abdominal distension and average length of hospital stay in group A were shorter than those in group B (P＜0.05). There was no significance in the incidence of complications between the two groups (P＞0.05). The remission time of abdominal pain and abdominal distension and the average length of hospital stay in group C were shorter than those in group D (P＜0.05). No significant difference was found in the incidence of complications between the two groups (P＞0.05). After treatment, the plasma diamine oxidase activity was lower in group A than in group B, and lower in group C than in group D (P＜0.05). There was no significant difference in the incidence of adverse reactions between group A and group B (P＞0.05) as well as between group C and group D (P＞0.05). 
Conclusion Administration of somatostatin within 24 h after the onset of acute pancreatitis can effectively improve the clinical efficacy, shorten the duration of treatment, and promote the improvement of intestinal mucosal barrier function, with good safety. 

Key words: pancreatitis, somatostatin, treatment outcome