A survey of electronic drug information resources and identification of problems associated with the differing vocabularies used to key them.

Abstract Drug information resources are increasingly becoming electronically available. They differ in scope, granularity, and purpose. These considerations have shaped the selection of dissimilar drug name keys, complicating access. An abbreviated and simplified historical context of the development of official controlled vocabularies and their relationships is followed by a review of the kinds of information available in several electronic drug information resources. The key vocabularies used are discussed with examples. Problems using the differing terms of the resource vocabularies are identified.