The so-called diffuse gastric cancer, also called medullary gastric cancer, is a type of gastric cancer with the following causes: 1) it is related to gastritis, such as superficial gastritis, atrophic gastritis, erosive gastritis, and positive H. pylori test; 2) it is related to environmental factors, such as high nitrate content in high salt areas, which is related to the occurrence of gastric cancer; 3) moldy food, such as aflatoxin, which is also related to the occurrence of gastric cancer when consumed for a long time; 4) it is also related to the destruction of gastric mucosa due to rough eating.