Abstract: The present invention provides a device and method for determining the quantity and identity of a substance ingested by a user. A detectable material such as barium sulfate is formed into a marker and mixed with a foreign substance such as pills, capsules, caplets, poisons or other hazardous substances. This detectable marker resides in the individual's digestive tract until passed. This material is detectable by use of X-ray equipment or a fluoroscope allowing the attending physician to "see" into the individual's digestive tract to determine the quantity of foreign substance ingested by counting the number of markers. Further, if the detectable markers have a unique geometric shape, the physician can identify the ingested substance associated with that shape of marker.