There's now medicine that knows whether you're following the doctor's orders, said Stephanie M. Lee at BuzzFeed. Silicon Valley's Proteus Digital Health makes a "smart pill" that wirelessly alerts an app after it's been swallowed. The pill uses "digestible sensors" made from copper and magnesium that react with stomach acid "to send a tiny electrical signal," which is picked up by a Band Aid–like patch worn on the skin.

That patch then alerts the Proteus app, which can send reminders to both the patient and doctor if a dose is missed. Proteus executives say their goal is to "fix a long-standing and often fatal problem": missed medication, which causes about 125,000 deaths annually in the United States alone. Privacy advocates, however, worry that a new era of wireless health could usher in "unparalleled new forms of surveillance."