We searched the MEDLINE, HEALTHSTAR, EMBASE, Cochrane Collaboration, and Best Evidence databases for prospective trials, retrospective trials, meta-analyses, and systematic reviews addressing early switch from parenteral to oral antibiotics and early discharge in patients with CAP. The following medical subject headings were searched: pneumonia, respiratory tract infections, community-acquired infections, infection, guidelines, economics, meta-analysis, prospective studies, randomized controlled trials, controlled clinical trials, treatment outcome, treatment failure, hospitalization, antibiotics, patient discharge, length of stay, quality of health care, outcome and process assessment (health care), quality assurance (health care), and total quality management. In addition, a literature search was performed based on the following title words: switch, conversion, intravenous to oral, parenteral to oral, community-acquired, pathway, guideline, quality, outcome, and discharge. A study was defined as having an early switch and early discharge strategy if it described a method or intervention designed to shorten LOS by recommending early switch, early discharge, or both from the hospital. The search was limited to English-language articles published between January 1, 1980, and March 31, 2000, human subjects, and clinical trials. Exclusion criteria applied to articles included the following: (1) a less rigorous study design (a retrospective or noninterventional study, review article [unless specifically addressing early switch from parenteral to oral antibiotics, early discharge, or both]; a letter; an editorial; a case study; a decision analysis; a consensus statement; a highlight from a conference; or an abstract); (2) a specific patient population (not specific for CAP, outpatient, aged <18 years, infected with the human immunodeficiency virus, has the acquired immunodeficiency virus syndrome, underwent transplantation, or has cystic fibrosis); (3) a nonbacterial cause (mycobacterial, fungal, or viral); (4) a nonclinical evaluation (in vitro activity, pharmacological features, or cytokines); (5) the study primarily addresses an issue not related to early switch from parenteral to oral antibiotics, early discharge, or both (no LOS evaluation, cause, epidemiological features, specific pathogen, admission decision, diagnosis or diagnostic workup, adverse drug reactions, antibiotic resistance, complications, or prevention); or (6) absence of criteria for switch, recommended day of switch, or recommended minimum number of days of parenteral treatment.