The bibliographic databases PASCAL BIOMED and MEDLINE, available both at SilverPlatter, were compared for their coverage of clinical medicine. The main objective of the study was to identify the information in PASCAL BIOMED that is supplementary to MEDLINE. In PASCAL BIOMED and MEDLINE 10 searches were performed, all limited to publication year 1996. Search profiles in PASCAL BIOMED were free text only, while in MEDLINE they were mainly composed of MeSH headings, with additional free text. Search results were analysed for numbers of (relevant) references retrieved, unique and duplicate references, precision and uniqueness ratio. Also the presence of abstracts in both databases, and the abstract language and the presence of English descriptors and identifiers in PASCAL BIOMED were studied. MEDLINE contained more relevant information than PASCAL BIOMED on nearly all topics studied. The precision of the PASCAL BIOMED searches varied from 29 to 87% (median = 68%) and of the MEDLINE searches from 20 to 91% (median = 66%). The uniqueness ratio in PASCAL BIOMED varied from 0 to 33% (median = 20%) and in MEDLINE from 28 to 83% (median 37%). Considering the numbers of relevant and unique references retrieved, MEDLINE performed better than PASCAL BIOMED. Yet a sizeable proportion of the relevant references were unique to PASCAL BIOMED. Probably PASCAL BIOMED would have performed better if lists of descriptors had been accessible in the database, preferably with support to trace them.