If you've got actual blood mixed in with your BM, it probably isn't anything to really get worried about. It would indicate a cut, hemorrhoids, or piles. If you've got internal bleeding your stool will be black if it's black as night go to the ER.
A little bit of bright red blood indicates a strain or cut. Could be from constipation, diet or hemmoroids. If your stool is dark black with blood bits, go immediately. Try changing your diet to include more fiber to help eliminate future constipation.
Have u eaten or drank anything red recently ? I know that sounds strange but when my hubby was in hospital for cancer surgery they wouldn't let him eat or drink anything red because they'd had patients flip over red in their stool or vomit it looked like blood but turned out to be the colouring in what they'd eaten. That being said if it has happened more than once u should get it checked out cause if it is blood u could have a serious problem