Cloth pads are made to be very absorbent. Most have a leakproof PUL layer, which prevents menstrual fluid from soaking through the pad. Of course, just like disposable pads, it's possible to leak off the sides if you wear it for too long. The wings that snap around the underwear helps to keep the sides of your undies dry, but of course, it is best to change them out before they become totally saturated.