Introduction: EMBASE, published by Elsevier in the Netherlands, is the principal European general health care database. Started in 1974, EMBASE currently indexes over 3000 journals, of which about 1000 are not indexed in MEDLINE. It is especially strong in pharmacology, and is likely to be the most important source of RCTs after MEDLINE. It is widely recognized, however, that the quality of methodological indexing in EMBASE was until recently relatively poor, and it is therefore difficult to locate reports of RCTs. In 1993, Carol Lefebvre, in consultation with others, developed a sensitive search strategy for RCTs in MEDLINE. Over the past two years, efforts within the Cochrane Collaboration to enhance MEDLINE (1975-93) using this search strategy have resulted in over 40,000 reports of trials being identified and subsequently retagged by the US National Library of Medicine for MEDLINE.

Objective: To devise and evaluate a sensitive search strategy for EMBASE.

Methods: Search terms (both free-text and from the controlled vocabulary) are being identified and tested for sensitivity and precision. The strategy will be developed, based on these data.

Results: The results will be presented in the form of tables of sensitivity and precision data, together with the final search strategies for the main EMBASE providers on CD-ROM (eg OVID and SilverPlatter) and online (eg DataStar/Dialog and BIDS).

Discussion: As Collaborative Review Groups attempt to build up their trials registers, they are increasingly looking to sources such as EMBASE to supplement the trials identified through MEDLINE, or by handsearching specialized journals. The sensitive search strategy should facilitate this activity, and should be of benefit to those developing specialized registers, and to those preparing systematic reviews.