Your feet are microbial hotspots. The area between your toes is packed with sweat glands, and when we wrap our feet in socks and shoes, we trap that moisture in a warm, humid cocoon that’s ideal for microbial growth. In fact, your feet may be home to a miniature rainforest of bacteria and fungi, with anywhere from 100 to 10 million microbial cells per square centimeter of skin surface.