US regulators have approved the first pill that can be digitally tracked through the body. The tablets have an ingestible sensor embedded inside them that records that the medication has been taken. A patch worn by the patient transmits this information to their smartphone. The information can also be sent to the prescribing doctor, if the patient consents to this. Experts hope it could improve medication compliance, although the company that makes the tablets says this has not been proved for their product.