In gastroenterology outpatient and inpatient clinics, we often see worried patients who come with gastroscopy and pathology reports of atrophic gastritis to consult: “Director, my stomach has atrophied, is the next step gastric cancer? Is this disease very dangerous, how should I treat and prevent it in general, etc.”. Patients carry different degrees of tension and anxiety. So, what is chronic atrophic gastritis? When exactly will cancer occur? Let’s find out now. Chronic atrophic gastritis is a chronic digestive disease characterized by atrophy of the epithelium and glands of the gastric mucosa, reduction in number, thinning of the gastric mucosa, thickening of the mucosal base, or pyloric glandular hyperplasia and intestinal glandular hyperplasia, or atypical hyperplasia. The causes are mainly related to Helicobacter pylori (HP) infection, smoking, alcohol consumption, food irritation, drugs that damage the gastric mucosa, immunity and other factors. Most chronic atrophic gastritis have a good prognosis. What is the probability of chronic atrophic gastritis becoming cancerous? Only a small percentage of cases are cancerous (most studies have found a cancer rate of no more than 3%). Atrophic gastritis alone is only a background disease for gastric cancer and is seen as precancerous when further intestinal epithelial metaplasia and heterogeneous hyperplasia occur. The evolution of chronic atrophic gastritis into gastric cancer generally goes through the following steps: intestinal epithelial hyperplasia → heterogeneous hyperplasia → gastric cancer. Especially, atrophic gastritis with moderate or above intestinal metaplasia and heteroplasia has more risk of cancer. It is worth noting that once atypical hyperplasia of gastric mucosa occurs, the chance of carcinogenesis increases significantly. Therefore, early detection, early diagnosis and early treatment by gastroscopy are especially important. In addition, it is equally important to maintain an optimistic attitude in life and diet, to develop good eating habits and to avoid stimulating diet nights.