More than half of clinical personnel say they use a phone or tablet on the job, and for good reason. A cellphone is a handy—some would argue essential—tool for carrying out medical tasks like calculating drug dosages, running through preop checklists, reviewing skills videos, performing vision tests, and offering consultations on the fly. The problem is that 90 percent of health care personnel never clean their devices. In the course of a day’s work, a nurse or doctor’s phone can be splashed, splattered, or smeared with wound drainage, blood, or god-knows-what other bodily dreck. Handling the device can transfer bacteria to the ears, nostrils, and hands. And bacteria parked on a Galaxy S9 screen or a My Little Pony iPhone case can live for months. If the germs are lucky, they’ll get to cross-contaminate something the provider later touches—a nice fresh incision, a cozy catheter, or a warm ventilator tube, say. The result may be a health care–associated infection. Three percent of hospital patients per year in the United States will develop a health care–associated infection, and about 72,000 patients will die of one. Mobile devices are a known source of the agents that cause these infections.