Colorectal cancer is insidious, early clinical symptoms are not obvious and easy to be ignored, early stage is often seen only positive fecal occult blood, those who have the following manifestations in middle age or above with unknown reasons should be alerted to the possibility of colon cancer: 1, recent changes in bowel habits, such as increased number of bowel movements, diarrhea, constipation, etc.; or persistent abdominal discomfort, hidden pain or abdominal distension, when there is intestinal obstruction, the abdominal pain is aggravated or paroxysmal colic. 2.Blood in the stool or pus-blood stool. 3.If abdominal mass is palpated, it is mostly the tumor itself, sometimes it may be the accumulation of feces in the lumen of the intestine near the obstruction, most of the masses are hard and nodular, if it is transverse colon or sigmoid colon cancer, it has a certain degree of activity. 4.Systemic symptoms, due to chronic blood loss, cancer festering infection, toxin absorption, etc., patients may have progressive anemia and weight loss, weakness, low fever, etc. 5.Late stage cancer symptoms such as hepatomegaly, jaundice, swelling, ascites, enlarged supraclavicular lymph nodes may appear. If one or more of the above symptoms appear, you should be alert, do not diagnose the disease on your own and use medication on your own, but go to a regular hospital for examination to avoid delaying the disease and losing the best time for treatment.