Stay fresh “down there” by following fool-proof guidelines for maxi-pad use. First off, change the thing every four hours, explains Dr. Adelaide Nardone, gynecologist and medical advisor to the Vagisil Women’s Health Center. “As blood dries, it smells,” she says. Bacteria get into the pad, and the blood begins to decompose (hold your nose) and, well, we’ll spare you the rest. This is a normal, natural process. But to keep odor-free, put on a fresh pad when you see a lot of blood on it, even if it’s only been an hour or two.