While blood in the stool may be a symptom of colon rectal cancer, there are several other reasons and illnesses that could also cause blood in the stool. In fact, rectal bleeding is a relatively common problem and is typically not serious, unless it is prolonged.
FX has posted a question very similar to yours. Please check out Blood During Wiping for more information. Also, to be on the safe side, FX recommends that you see a doctor to make sure that everything is okay. If you live in Northern New Jersey, please call the Adolescent/Young Adult Center for Health at (973) 971.6475.