It is impossible to judge whether there is bowel cancer by the thickness of stool alone. Bowel cancer needs to be diagnosed by combining its medical history, symptoms and signs, and auxiliary examination. 1. Medical history: Bowel cancer is related to heredity, chemical carcinogens, ulcerative colitis, colorectal polyps, colorectal adenoma and other factors. 2. Symptoms and signs: patients present with diarrhea, abdominal mass, constipation, bloody stools, mucus stools, feeling of incomplete bowel movement, abdominal pain and other symptoms. In addition, if the intestinal lumen is narrowed, it may lead to fecal thinning, fecal deformation and other changes in stool characteristics. 3. Adjunctive examination: positive result of fecal occult blood test after electron endoscopy which suggests that cauliflower pattern or nodular mass is observed microscopically, and positive result of tumor marker test which suggests that there may be intestinal cancer. Other imaging tests, such as abdominal CT, PET-CT, and X-rays can also assist in the diagnosis. Therefore, it is recommended that after symptoms appear, one must choose to consult a doctor in time, after scientific examination, to clarify the condition and follow the doctor’s instructions to standardize the treatment as early as possible.