I have bright red blood on my stool my age is 19 i have no family history of any cancer. what does this sound like?

A scrape: Passing something relatively hard in the stool produces a streak down the side. This is not a warning of cancer. If this becomes a common problem, get with your physician and talk about diet and a possible stool softener.

DDx: Cancer is unlikely in a 19 year old without a family history, but not impossible. The most likely causes in the differential diagnosis (ddx) includes: hemorrhoids (internal or external), hard stool with a small tear/laceration (as already answered), ulcer (usually not bright red), or an inflammatory bowel disease (eg crohn's, ulcerative colitis). Talk to your md or gastroenterologist.