Take it from someone whose job involved getting splashed with blood---always cold water, with NO soap. Keep running it under cold water and rubbing the fabric against itself, or use a nail brush or toothbrush to rub it. If that doesn't work, soak it overnight with cold water (no soap) and try rubbing again. If there is still a faint stain, then try the diluted peroxide as previously explained. Be sure to rinse well immediately. It's not ruined, but it may take some work. Good luck!