Abstract: OBJECTIVE To explore into the effect of Erbao Granule of different dosages on the Substance P expression of rat models with infantile anorexia.METHOD Infant rats were fed improperly to produce infantile anorexia models and immunohistochemical method was used to observe histiomorphological changes and changes in the content of Substance P.RESULT The content of Substance P in the basal part of the stomach and in the jejunal myenteric nerve plexus of the rat model decreased markedly as compared with the control group(P<0.05).After the use of Erbao Granule,Substance P content increased greatly(P<0.05),but with no difference between the small dosage group and the control group(P>0.05).Morphologically,there were varying degrees of changes in the gastrointestinal tissue in the model group and large dosage group.CONCLUSION Erbao Granule can promote Substance P secretion,thus improve appetite and speed up growth.