Some of the symptoms include, bleeding while stooling and lower abdominal pain. More symptoms are diarrhea and constipation. Colon cancer symptoms are not always obvious, but you can learn what these symptoms look and feel like. In the early stages of the cancer, people that have this will have no symptoms at all. There are two types of colon cancer symptoms, the Local and the Systematic. Local colon cancer symptoms affect your bathroom habits and the colon itself. Some of the more common local symptoms of colon cancer include: changes in your bowel habits; constipation; diarrhea; bright red or dark red blood in your stools or black, dark colored, "tarry" stools; stools that are thinner than normal; and, abdominal discomfort, bloating, frequent gas pains, or cramps. Systemic colon cancer symptoms are those that affect your whole body, such as weight loss, and include: unintentional weight loss; loss of appetite; unexplained fatigue; nausea or vomiting; anemia; and, jaundice.