INGESTIBLE EVENT MARKER SYSTEMS THAT INCLUDE AN INGESTIBLE EVENT MARKER (I.E., AN IEM) AND A PERSONAL SIGNAL RECEIVER ARE PROVIDED. EMBODIMENTS OF THE IEM INCLUDE AN IDENTIFIER, WHICH MAY OR MAY NOT BE PRESENT IN A PHYSIOLOGICALLY ACCEPTABLE CARRIER. THE IDENTIFIER IS CHARACTERIZED BY BEING ACTIVATED UPON CONTACT WITH A TARGET INTERNAL PHYSIOLOGICAL SITE OF A BODY, SUCH AS DIGESTIVE TRACT INTERNAL TARGET SITE. THE PERSONAL SIGNAL RECEIVER ES CONFIGURED TO BE ASSOCIATED WITH A PHYSIOLOGICAL LOCATION, E.G., INSIDE OF OR ON THE BODY, AND TO RECEIVE A SIGNAL THE IEM. DURING USE, THE IEM BROADCASTS A SIGNAL WHICH IS RECEIVED BY THE PERSONAL SIGNAL RECEIVER. FIG. 3
