Chronic atrophic gastritis with intestinalization is considered to be cancerous, and it is recommended to carry out medication and surgical treatment after complete examination. Chronic atrophic gastritis with enteritis refers to the reduction of inherent glands in gastric mucosal epithelium, accompanied by mucosal and glandular atrophy, part of gastric glandular cells are replaced by intestinal epithelial cells, which belongs to pre-cancerous lesions, and cancerous changes in stomach are considered to be possible when the patient has a sudden weight loss. After this situation, gastroscopy, pathological examination of gastric mucosa, hematological examination of tumor markers and other auxiliary examinations are needed to clarify whether there is cancerous lesion of gastric mucosa, and drug treatment or surgical treatment should be carried out according to the results of the examination. Chronic atrophic gastritis with enterocolitis suddenly lost weight, it is recommended that patients go to the hospital as soon as possible, to clarify the cause of the disease, early treatment, so as not to cause serious consequences.