It may seem strange that something you do for your teeth can have any effect on your heart. Doctors have come up with a few ideas about how flossing works to keep your heart healthy. One idea is that the germs that hurt your teeth can leave the mouth and travel into your blood. Germs that get into the blood can then attrack your heart. Another idea is based on the fact that when there are too many fights in your mouth, the body tries to fight these germs. For some reason, the way the body fights these mouth germs may end up weakening the heart over time.