Objective To elucidate the effect of early enteral nutrition support(ENS) for the patients with severe acute pancreatitis(SAP).Methods Fifty patients with SAP were at random divided into two groups: enteral nutrition group(EN group, 25 cases), parenteral nutrition group(PN group, 25cases). PN group was given total parenteral nutrition(TPN),125 kJ/(kg?d) of energy, nitrogen intake:0.20g/(kg?d). In EN group, the naso intestinal tube was placed posterior to ligament Treitz. Since the 1st day nutrilion was infused.Results On the first?4th day, the serum RBP?PA levels were obviously decreased (P