The Food and Drug Administration has approved an ingestible digital senor that can track physical health with the assertion that patients are not taking their medication regularly and need a tracking device inside their body to assist them in their medical care

http://beginningandend.com/fda-approves-sale-of-pills-with-rfid-mircochip/

Many older patients try to save money by taking only half of their medication -- trying to make last longer because it is so expensive.  The problem is, then they aren't taking the correct dosage of meds to it to work.