This study examines the indexing of drugs in the literature and compares actual drug indexing to stated indexing policies in selected databases. The goal is to aid health science information specialists, end-users, and/or non-subject experts to improve recall and comprehensiveness when searching for drug information by identifying the most useful search terms (or search term combinations) when seeking information about a drug. This study uses a comparative methodology to evaluate the indexing of 30 drugs within four online databases (Analytical Abstracts; BIOSIS PREVIEWS; Pharmaceutical News Index; and SCISEARCH). The results underscore the need for a basic understanding of pharmaceutical nomenclature; effective use of chemical dictionary files; awareness of indexing differences among databases; and a well-planned search strategy that includes flexibility to make changes as necessary in order to complete a successful search. A list of the drugs used is appended. (Contains 20 references.) (Author/JLB)