PURPOSE OF REVIEW: To review, summarize and update our present understanding of toxic anterior segment syndrome. RECENT FINDINGS: Toxic anterior segment syndrome has emerged within the last 2 years as a complication of increasing frequency following uneventful cataract surgery. Over 100 North American clinics reported toxic anterior segment syndrome cases to a specially constituted task force over a 4-month period in 2006. Toxic anterior segment syndrome is now recognized as a specific, noninfectious condition presenting as anterior segment inflammation that occurs within days of surgery and is responsive to topical steroids. Specific causes have been identified such as endotoxin contamination of balanced salt solutions and antibiotic ointment accessing the anterior chamber, although most cases appear to result from inadequate instrument sterilization and preparation. Outcomes are usually excellent, but delayed treatment and severe cases may result in glaucoma and persisting corneal edema requiring penetrating keratoplasty. SUMMARY: Toxic anterior segment syndrome has become a significant complication of cataract surgery. Rapidly increasing knowledge made possible by ophthalmic organizations and the prompt dissemination of research findings, however, appear to have provided the information necessary to help prevent and resolve this condition.