2. Diarrhea
If you suffer from diarrhea for more than a couple of weeks, it may be an early symptom of colon cancer.
When a tumor partially obstructs the bowel, it can cause alternating constipation and diarrhea due to leakage of liquid stool.
You may also experience frequent gas, abdominal pain, nausea and vomiting. Plus, a tumor may irritate or narrow the lining of the intestine.
It is important to consult your doctor when you have diarrhea that lasts more than a few days, as it can lead to dehydration, drain your body of nutrients and signal other serious problems, such as cancer.