Abstract： Objective To determine the level and clinical significance of 5-hydroxytryptamine (5-HT) and intestinal fatty acid binding protein (iFABP) in patients of severe acute pancreatitis (SAP) with intestinal dysfunction. Methods The serum and urine in 42 cases of SAP with intestinal dysfunction were collected at day 1, 3 and 7 after admission, respectively. The numbers of bowel sounds were recorded. 20 health subjects were selected as the control. Results The numbers of bowel sounds in health subjects were 5.6 ± 2.3/min. The numbers of bowel sounds in SAP patients at day 1,3 and 7 were 2.3 ± 0.7/min, 1.7 ± 0.2/min and 3.1 ± 1.1/min, respectively;which were significantly lower than that in the control group (P < 0.01). The level of 5-HT in the control group was(86.7 ± 9.5)ng/ml, while the levels of 5-HT in the SAP patients at day 1, 3 and 7 were (112.0 ± 17.8) ng/ml, (130.5 ± 19.7) ng/ml, (107.9 ± 16.3) ng/ml. The level of urine iFABP in the control group was (90.5 ± 19.8) pg/ml, while the levels of urine iFABP in the SAP patients were (1250.2 ± 425.3) pg/ml, (1586.9 ± 523.4) pg/ml, (1154.6 ± 394.0) pg/ml. The levels of 5-HT and urine iFABP in the SAP patients all were significantly higher than those in the control group (P <0.01). The levels of 5-HT and urine iFABP in the SAP patients at day 3 were significantly higher than those in the day 1 and day 7, while there was no significant difference between the two groups. Conclusions Determination of serum 5-HT and urine iFABP in patients with early SAP could effectively evaluate the intestinal function, and it may have potential clinical significance.