Constipation
This can be a sign of many issues—usually meaning that the patient is not drinking enough water or not getting enough fiber. However, constipation may also be a sign of colon cancer, because the presence of polyps in the colon can slow the progress of food waste, making it hard to pass it out of the body.
Diarrhea
While constipation is usually the result of not getting enough fiber or water in the diet, diarrhea can be the result of excessive hydration. It can also be the effect of an illness, such as the flu. Diarrhea can be an early sign of colon cancer. If this happens frequently, you should speak with your doctor immediately.