AIM: To determine the role of acupuncture therapy in treating experimental gastric ulcer in rats.METHODS: Twenty-eight adult male Sprague-Dawley rats were randomly divided into four groups (pre-acupuncture group; acupuncture group; paradistance-acupuncture group;and control group), and pre-acupuncture, paradistanceacupuncture, and control groups received 5 μL acetic acid (200 mL/L HAc) injection after a same course of electroacupuncture (EA) treatment (4 Hz, 0.6 mA, 0.45 ms,45 min for 4 d). The rats in these three groups recovered within 4 d. The acupuncture group received EA therapy for 4 d, after HAc injection. The stomach was dissected to compare the pathological structures of ulcer. Also c-Fos activation in the nuclei of solitary tract (NTS) was observed under microscope after regular immunohistochemistry staining of brain stem sections.RESULTS: The number of ulcers was different among the four groups, especially between control group and paradistance-acupuncture group or pre-acupuncture group. In the latter group, the number of ulcers was much less. The gastric ulcer area was consistent with the histopathological results, indicating that pre-acupuncture had an obvious therapeutic effect on gastric ulcers.Acupuncture had a very modest effect and paradistanceacupuncture had no effect on gastric ulcers. No therapeutic effect was found in the control group. Fos-Li neurons in NTS induced by noxious gastric ulcer showed a significant difference between pre-acupuncture and control groups.CONCLUSION: Acupuncture before ulceration can obviously alleviate ulcer. The production of c-Fos proves that the vagus nerve mediates the induction of c-Fos in nuclei of solitary tract following experimental ulceration,suggesting that parasympathetic afferents promote the process of noxious visceral stimulation.