AIM: To study the effects of He-Ne laser irradiation on experimental chronic atrophic gastritis (CAG) in rats. METHODS: Sixty-three male adult Wistar rats were randomly divided into five groups including normal control group, model control group and three different dosages He-Ne laser groups. The chronic atrophic gastritis (CAG) model in rats was made by pouring medicine which was a kind of mixed liquor including 2% sodium salicylate and 30% alcohol down the throat for 8 wk to stimulate rat gastric mucosa, combining with irregular fasting and compulsive sporting as pathogenic factors; 3.36, 4.80, and 6.24 J/cm2 doses of He-Ne laser were used, respectively for three different treatment groups, once a day for 20 d. The pH value of diluted gastric acid was determined by acidimeter, the histopathological changes such as the inflammatory degrees in gastric mucosa, the morphology and structure of parietal cells were observed, and the thickness of mucosa was measured by micrometer under optical microscope. RESULTS: In model control group, the secretion of gastric acid was little, pathologic morphological changes in gastric mucosa such as thinner mucous, atrophic glands, notable inflammatory infiltration were found. After 3.36 J/cm2 dose of He-Ne laser treatment for 20 d, the secretion of gastric acid was increased (P<0.05), the thickness of gastric mucosa was significantly thicker than that in model control group (P<0.01), the gastric mucosal inflammation cells were decreased (P<0.05). Morphology, structure and volume of the parietal cells all recuperated or were closed to normal. CONCLUSION: 3.36 J/cm2 dose of He-Ne laser has a significant effect on CAG in rats. AIM: To study the effects of He-Ne laser irradiation on experimental chronic atrophic gastritis (CAG) in rats. METHODS: Sixty-three male adult Wistar rats were divided divided into five groups including normal control group, model control group and three different dosages He-Ne laser groups. The chronic atrophic gastritis (CAG) model in rats was made by pouring medicine which was kind of mixed liquor including 2% sodium salicylate and 30% alcohol down the throat for 8 weeks to stimulate rat gastric mucosa, combining with irregular fasting and compulsive sporting as pathogenic factors; 3.36, 4.80, and 6.24 J / cm2 doses of He-Ne laser were used, respectively for three different treatment groups, once a day for 20 d. The pH value of diluted gastric acid was determined by acidimeter, the histopathological changes such as the inflammatory degrees in gastric mucosa, the morphology and structure of parietal cells were observed, and the thickness of mucosa was measured by micrometer under optic al microscope. RESULTS: In model control group, the secretion of gastric acid was little, pathologic morphological changes in gastric mucosa such as thinner mucous, atrophic glands, notable inflammatory infiltration were found. After 3.36 J / cm2 dose of He-Ne laser treatment for 20 d, the secretion of gastric acid was increased (P <0.05), the thickness of gastric mucosa was significantly thicker than that in model control group (P <0.01), the gastric mucosal inflammation cells were decreased (P <0.05). Morphology, structure and volume of the parietal cells all recuperated or were closed to normal. CONCLUSION: 3.36 J / cm2 dose of He-Ne laser has a significant effect on CAG in rats.