Bowel cancer and dark spots on lips are not absolutely related, the latter may be caused by the former. 1. Black spot on lips belongs to a relatively common clinical manifestation, and its etiology is relatively complicated, which may be caused by skin disease, pigmentation, cosmetic stimulation, and of course, may also be caused by bowel cancer. However, the relationship between the two is not absolute, and it can only be said that the appearance of black spots on lips may be caused by bowel cancer. In addition, the adverse reactions in chemotherapy of bowel cancer patients include hyperpigmentation, which may appear dark spots on skin and lips. 2. Typical symptoms of bowel cancer are still blood in stool, abdominal discomfort, acute and severe pain, etc. Only a small number of patients may have black spots on lips, such as accompanied by wasting, abnormal stool, etc., which need to be determined by colonoscopy, abdominal CT, pathological tissue biopsy, etc. in a timely manner. 3. If discomfort occurs, you should go to the hospital in time, and under the guidance of the doctor for proper treatment.