AIM:To study the role of capsaicin-sensitive afferent nerves in Helicobacter pylori (H.pylori) positive chronic gastritis before and after eradication.METHODS:Gastric biopsy samples were obtained from corpus and antrum mucosa of 20 healthy human subjects and 18 patients with H.pylori positive chronic gastritis (n=18) before and after eradication.Tradi-tional gastric mucosal histology (and Warthin-Starry silver impregnation) and special histochemical examina-tions were carried out.Immunohistochemistry for cap-saicin receptor (TRVP1),calcitonin gene-related peptide (CGRP) and substance P (SP) were carried out by the labeled polymer immunohistological method (Lab VisionCo.,USA) using polyclonal rabbit and rat monoclonal antibodies (Abcam Ltd.,UK).RESULTS:Eradication treatment was successful in 16 patients (89%).Seven patients (7/18,39%) re-mained with moderate complaints,meanwhile 11 pa-tients (11/28,61%) had no complaints.At histological evaluation,normal gastric mucosa was detected in 4 patients after eradication treatment (4/18,22%),and moderate chronic gastritis could be seen in 14 (14/18,78%) patients.Positive immuno-staining for capsaicin receptor was seen in 35% (7/20) of controls,89% (16/18,P < 0.001) in patients before and 72% (13/18,P < 0.03) after eradication.CGRP was positive in 40% (8/20) of controls,and in 100% (18/18,P < 0.001) of patients before and in 100% (18/18,P < 0.001) after eradication.The immune-staining of gastric mucosa for substance-P was positive in 25% (5/20) of healthy con-trols,and in 5.5% (3/18,P > 0.05) of patients before and in 0% of patients (0/18,P > 0.05) after H.pylori eradication.CONCLUSION:Distibution of TRVP1 and CGRP is altered during the development of H.pylori positive chronic gastritis.The immune-staining for TRVP1,CGRP and SP rwemained unchanged before and after H.py-lori eradication treatment.The capsaicin-sensitive affer-entation is an independent from the eradication treat-ment.The 6 wk time period might not be enough time for the restituion of chronic H.pylori positive chronic gastritis.The H.pylori infection might not represent the main pathological factor in the development of chronic gastritis AIM: To study the role of capsaicin-sensitive afferent nerves in Helicobacter pylori (H.pylori) positive chronic gastritis before and after eradication. METHODS: Gastric biopsy samples were obtained from corpus and antrum mucosa of 20 healthy human subjects and 18 patients with H . Pylori positive chronic gastritis (n = 18) before and after eradication. Tradi-tional gastric mucosal histology (and Warthin-Starry silver impregnation) and special histochemical examina- tions were carried out. Immunohistochemistry for cap-saicin receptor (TRVP1) gene-related peptide (CGRP) and substance P (SP) were carried out by the labeled polymer immunohistological method (Lab Vision Co., USA) using polyclonal rabbit and rat monoclonal antibodies (Abcam Ltd., UK) .RESULTS: Eradication treatment was successful Seven patients (7 / 18,39%) re-mained with moderate complaints, meanwhile 11 pa-tients (11/28, 61%) had no complaints.A histological evaluation, normal gastric mucosa was detected in 4 patients after eradication treatment (4 / 18,22%), and moderate chronic gastritis could be seen in 14 (14 / 18,78%) patients. Positive immuno-staining for capsaicin receptor was seen in 35% (7/20) of controls, and in 100% (16/20, P <0.001) in patients before and 72% (13/18, P <0.03) after eradication.CGRP was positive in 40% (8/20) of controls 18 of 18, P <0.001) of patients before and in 100% (18/18, P <0.001) after eradication. Immune-staining of gastric mucosa for substance-P was positive in 25% (5/20) of healthy con-trols, and in 0% of patients (0/18, P> 0.05) after H. pylori eradication. CONCLUSION: Distibution of TRVP1 and CGRP was altered during the development of H. pylori positive chronic gastritis. immune-staining for TRVP1, CGRP and SP rwemained unchanged before and after H. py-lori eradication treatment. the capsaicin-sensitive affer-entation is an independent from the eradication treat- ment The 6 wk time period might not be enough time for the restitution of chronic H.pylori positive chronic gastritis.The H.pylori infection might not represent the main pathological factor in the development of chronic gastritis