Background Intra-abdominal hypertension (IAH) is a recognized prognostic marker for severity of severe acute pancreatitis (SAP) and has a strong impact on the clinical course of SAP.Previous studies indicate that a Da-Cheng-Qi Decoction (DCQD) is beneficial in the treatment of SAP.The purpose of this study was to evaluate the effect of modified DCQD on IAH in patients with SAP.Methods Between January 2008 and December 2008,42 patients from the West China Hospital were randomized into either the DCQD or control group (n=21 in each group).Mortality,intra-abdominal pressure (lAP),Acute Physiology and Chronic Health Evaluation II (APACHE II) score,C-reactive protein (CRP),oxygenation index,Balthazar CT score,rate of renal failure,decompression rate,intensive care unit (ICU) transfer rate,and length of hospital stay (LOS) were compared between the two groups.Results Compared to the control group,the modified DCQD treatment significantly decreased lAP (P ＜0.05) and APACHE Ⅱ (P ＜0.05) scores on days 4-8,CRP on day 8 (P ＜0.01 ),renal failure rate (P ＜0.05),and LOS (P ＜0.05).The oxygenation index was significantly improved in the DCQD group compared with the control group (P ＜0.05).No significant differences in the Balthazar CT score,shock rate,ICU transfer rate,or mortality occurred between the two groups.Conclusions The modified DCQD can effectively relieve IAH and decrease LOS for patients with SAP.Larger clinical trials are needed to confirm these findings.