Toxic anterior segment syndrome is a sterile postoperative inflammatory reaction, with typical clinical features and serious secondary complications. The causes of TASS are numerous and varied. It is informed that irrigating solutions and ophthalmic viscosurgical devices, ophthalmic instrument contaminants, ocular medications and intraocular lenses are correlation factors. TASS is easy to be confused with the infectious endophthalmitis and difficult to diagnose. It is reported that the steroid therapy for TASS is effective but the mainstay of treatment for TASS centers on prevention.