bacteria are everywhere!
If you don't scrub your shower curtain, you're asking for trouble. These plastic sheets are flooded with bacteria that can cause nasty infections says Norman Pace, a microbiologist at the University of Colorado, Boulder.
The bacteria probably feed on volatile organic chemicals shed from human bodies, says Pace, rather than on soap. "When you cough, belch or fart, you're putting a lot of organic chemistry in there," he says. Chemicals called plasticizers, which make shower curtains more flexible, could also feed bacteria, he suggests.