When his chemotherapy patients leave the hospital to continue treatment at home, Edward Greeno faces a new challenge. He can no longer ensure they’re taking their medicine. Greeno, the medical director of the Masonic Cancer Clinic at the University of Minnesota, has come to realize that some patients, like children hiding naughty behavior from a parent, will fudge the truth to avoid his disapproval, even when their health is at risk. To combat patients’ fibbing and forgetfulness, Greeno has begun deploying a new tool in recent months: a pill embedded with a tiny, ingestible sensor.