Objective To study the neuropathological changes of gastrin and substance P(SP) in the intermuscular and submucous nerve plexus of the colonic walls in patients with delayed motor constipation(DMC).MethodsGastrin and rabbit SP polyclonal antibiotics were used to make an immunohistochemical staining of the samples of different segments obtained from 10 patients with DMC and 8 normal subjects(control group) for a comparative observation as well as a relative semi-quantitative analysis.Results The immune positive nerve cells of gastrin and SP in the intermuscular nerve plexus of colon with DMC were markedly reduced; no differences in the immune response of gastrin and SP in the mucous nerve plexus were found between the two groups(P＜0.01). With routine HE staining, focal inflammation occurred in the mucous membrane of DMC colon and that the neuronal vacuolus of the intermuscular nerve plexus degenerated, reduced and even disappeared. Conclusion The abnormal changes of the neural structure in the immune reponse of gastrin and SP in the intermuscular nerve plexus of colon with DMC might be related to reduction of gastrin and SP peptide neuron or dysfunctional.