AIM: To investigate the effect of Chaiqinchengqi decoction (CQCQD) on sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) mRNA expression of pancreatic tissues in acute pancreatitis (AP) rats.METHODS: Thirty Sprague-Dawley (SD) rats were randomized into control group, AP group and CQCQD group (n = 3 × 10). The rats in the CQCQD group were intragastrically administered with CQCQD (10 mL/kg every 2 h) after induction of AP by intraperitoneal injection of caerulein (50 μg/kg.h × 5) within 4 h. At 6 h after the induction of AP model, pancreatic tissues were collected for the pathological observation, mRNA extraction for determination of SERCAl and SERCA2 mRNA expression or pancreatic acinar cell isolation for measurement of fluorescence intensity (FI) of intracellular calcium ion concentration [Ca2+].RESULTS: There was no expression of pancreaticSERC41 mRNA in the control group and the AP group.The expression of pancreatic SERCA2 mRNA in the APgroup was down-regulated (expression ratio = 0.536;P = 0.001) compared with the control group, while that in the CQCQD group was up-regulated (expression ratio =2.00; P=0.012) compared with AP group. The FI of intracellular [Ca2+] of pancreatic acinar cells in the AP group (138.2 + 23.1) was higher than the C group (111.0+ 18.4) and the CQCQD group (118.7±15.2 ) (P < 0.05)and the pancreatic pathological score in the CQCQD group was lower than that in the AP group (5.7±1.9 vs 9.2 ± 2.7, P < 0.05).CONCLUSION: CQCQD can up-regulate the expression of SERCA2 mRNA of pancreatic tissues, reduce intracellular calcium overload and relieve pancreatic tissue lesions.