This review, made at congressional request, examined the Food and Drug Administration's (FDA) handling of adverse drug reaction (ADR) reports. The FDA is responsible for ensuring that marketed drugs are safe and effective, and operates a program to receive and analyze information on adverse drug reactions and recommend corrective regulatory actions when necessary. A major problem identified was the under reporting of serious adverse drug reactions to FDA by hospitals and health professionals. Currently, reporting of ADRs to FDA by hospitals and health professionals is strictly voluntary. The FDA needs to seek out ways to augment the limited information it now receives regarding ADR occurrences. Recommendations call for steps the FDA can take to improve oversight of this area. The FDA agreed with our recommendations and is taking action to strengthen the ADR reporting and handling process.