In addition to Mary’s wonderful suggestion of Lestoil, I have found that Fels-Naptha laundry soap is the absolute best for blood stains. Of course, it works best to attack the stains when they are fresh. But even on dried stains, Fels-Naptha is the only thing that has worked.
I run the bar under warm water and then just rub it right on the stain. If the stain is bad, I rub soap on both sides. I then throw the dirty garment into the washer and 99.9% of the time the stain has come out completely. One time, I had to repeat the steps and it was all gone. For less than $2 a bar at most grocery stores, this is a bargain you can’t miss!