PaperChase is a computer program that permits any physician or scientist to search the National Library of Medicine's MEDLINE data base of references to the biomedical literature. Written for the clinician rather than for the search librarian, PaperChase permits the user to search the entire MEDLINE collection of over 5,000,000 references published in 4,000 biomedical journals dating back to 1966. PaperChase is now available throughout the world to anyone who has a computer terminal or personal computer, and a modem. No special training is needed for a successful search. There is no user's manual. Users can search by title word, Medical Subject Heading, author's name, journal title, year of publication, language of publication, or any combination of the above. Users can read abstracts online, and they can request that a photocopy of the full text of any article be mailed to them.