Objective To investigate the effects of Simo decoction on ghrelin and calcitonin gene-related peptide (CGRP) in diabetic rats.Methods A total of 48 SD rats were divided into healthy control group,diabetes group (DM),DM treated with low dose Simo decoction group (DMTL),DM treated with medium dose Simo decoction group (DM-TM),DM treated with high dose Simo decoction group (DM-TH) and DM prevented with medium dose Simo decoction group (DMPM) ; there were eight rats in each group.The rats of DM group and other intervention groups were intraperitoneally injected with 1％ streptozotoein (STZ) to establish the model.The rats of healthy control group were injected with solvent.At eight weeks after the model successfully established,the rats of each intervention group were gavaged with low dose of Simo decoction (0.15 ml · kg-1 · d-1 ),medium dose of Simo decoction (1.5 ml · kg-1 · d-1 ) and high dose of Simo decoction (3.0 ml · kg-1 ·d-1 ) for two weeks; the rats of control group and DM groups were gavaged with equal volume of 0.9％NaCl.The rats of DM-PM group were gavaged with Simo decoction at 1.5 ml · kg-1 · d-1 for 10 weeks after the model successfully established.Rats were sacrificed at the end of drug intervention and gastric antrum tissues were dissociated for detecting the expression of ghrelin and CGRP by real time polymerase chain reaction (PCR).The data were analyzed by one way ANOVA and t test.Results There was no significant difference in ghrelin expression at mRNA level in gastric antrum tissues between diabetic rats and control group.However after intervened by low dose and medium dose of Simo decoction,the ghrelin expression increased (1.45 ± 0.34,1.87 ± 0.68 compared with 0.87 ±0.28,Dunnett's T3 test,P＜0.05).There was no effects of high dose Simo decoction on the expression of ghrelin in diabetic rats.There was no significant difference in ghrelin between DM-TM and DM-PM.The expression of CGRP at mRNA level in gastric antrum tissues of diabetic rats was significantly higher than that of control group (4.61 ± 1.67 compared with 1.06 ± 0.40,t =5.843,P＜0.01).There was no effects of low dose Simo decoction on CGRP expression of diabetic rats.The expression of CGRP of diabetic rats was down-regulated by medium and high dose of Simo decoction intervention.There was no significant difference in CGRP expression between DM-TM and DM-PM.Conclusions Simo decoction can promote ghrelin expression in gastric antrum of diabetic rats.The expression of CGRP in gastric antrum of diabetic rats significantly increased,but Simo decoction may down-regulate the expression of CGRP in gastric antrum of diabetic rats.