Intestinal polyp Yamada type I refers to intestinal polyps that are mound-shaped with a flat, wide base and only slightly elevated above the surface of the intestinal wall. Japanese scholars have proposed the classic Yamada typing based on the different morphologies of endoscopic colonic polyps, which are divided into four types. 1. Type I refers to polyps with a flat and wide base, slightly elevated on the surface of the intestinal wall, and without tips. 2. Type II refers to polyps with a more pronounced protruding base, hemispherical in shape, and without a well-formed tip. 3. Type III refers to a polyp with a prominent base that forms an acute angle with the surrounding intestinal wall mucosa and is spherical in shape. 4. Type IV refers to a polyp that is spherical in shape and has an obvious tip. The nature of the polyp cannot be determined by Yamada typing, so it is necessary to take a biopsy and send it to pathology for further clarification of the nature of the protruding part, and if necessary, follow the doctor’s instructions for the relevant treatment.