If the patient is in early stage of bowel cancer, it means that the tumor develops early, the tumor is small and no metastasis occurs, the patient will not have gastrointestinal tract dysfunction or malnutrition, so the patient will not lose weight. If the patient’s bowel cancer continues to progress, it is progressive bowel cancer or advanced bowel cancer, the patient will suffer from malnutrition, so he/she will lose weight, usually within 3 months or 6 months, the weight loss may reach 5kg or even 8kg. Most of the patients with early stage bowel cancer show frequent stools, thin stools or blood in stools, black stools, etc. Some patients have hidden pain in the abdomen, but some patients do not have any symptoms in the abdomen, and generally need to do colonoscopy to make a clear diagnosis.