Hello. Thank you for your question. The most common reason for seeingbblood in a bowel movement, in patients of this age, is a small abrasion near, or in, the anus. This is typically do to hard or large bowel movements. It is of no immediate concern. If it persists, however, adding fiber to the diet in order to soften the stools, will almost always alleviate the problem. If this doesn't work, or you have any other doubts or concerns, I recommend consulting with your doctor.