An automatic data collection system tracks articles by providing a robust electromagnetic (EM) field within an enclosure in which the articles are stored. Respective data carriers, such as RFID tags, attached to each article respond to the electromagnetic field by transmitting data identified with each article. An RFID scanner receives the transmitted RFID tag identification data and a processor compares the received identification data to a data base. The data base associates the identification data with data concerning the medical article to which the RFID tag is affixed, such as the name of the medicine, the size of the dose, and the expiration date. The processor is also programmed to keep track of the number of articles of a particular type remaining in the enclosure, to note receipt of an article in the enclosure, and to note removal of the article.