Practice guidelines are rapidly becoming preferred decision-makingresources in medicine, as advances in technology and pharmaceuticscontinue to expand. An evidence-based approach to the development ofpractice guidelines serves to anchor healthcare policy to scientificdocumentation, and in conjunction with practitioner opinion canprovide a powerful and practical clinical tool. Three sources ofinformation are essential to an evidence-based approach: a) anexhaustive literature synthesis; b) meta-analysis; and c) consensusopinion. The systematic merging of evidencefrom these sources offers healthcare providers a scientificallysupportable document that is flexible enough to deal with clinicallycomplex problems. Evidence-based practice guidelines, inconjunction with practice standards and practice advisories, areinvaluable resources for clinical decision making. The judicious useof these documents by practitioners will serve to improve theefficiency and safety of health care well.