1.Blood in stool and occult blood Blood in stool is a major manifestation of a digestive tract cancer. It may not be noticed at first, but if blood in stool is found in every stool, we must be alert! Cancer cells destroy the mucous membrane of the intestine and erode the blood vessels of the intestinal wall, which will cause blood in the stool. Of course the most common is to identify with hemorrhoids. 2. Nipple overflow and breast swelling Unusual overflow from non-lactating female nipples should be alerted. Especially bloody overflow. There is also a breast mass. If you find a breast mass, you should go to the hospital for an examination. 3. Increase in the number of stools or change in bowel habits According to our statistics, the increase in bowel habits is the most common symptom of rectal cancer in the elderly. It should be taken seriously. 4.Unexplained weight loss Nowadays, people are popular to lose weight, but if there is unexplained weight loss, it may not be good. It should be checked in hospital. Otherwise, it will be mistaken for the effect of weight loss and will delay the condition. 5, unexplained coughing up blood Coughing is a common symptom for us. For example, the cold. We all have the experience of coughing. However, if it is just a common cold and there is coughing blood, and it is fresh blood, or blood in the sputum, do not ignore it and you should go to the hospital for examination. 6. Weakness and anemia Our life is getting faster and faster, and it is common to have weakness and sub-health, but if we have significant weakness and pale face, we should pay attention to it. Pale face is not always the result of “whitening”, it may be anemia, and the cause may be chronic blood loss caused by cancer.