Toxic anterior segment syndrome (TASS) is a severe, acute, sterile intraocular inflammation that occurs the same day or in the early stages after intraocular surgery. It has been most commonly reported after phacoemulsification. We report 2 cases that developed TASS after sequential uneventful trabeculectomy surgeries, in which a quaternary ammonium compound was used for the disinfection of surgical instruments. Good outcomes were achieved, possibly related to the fast treatment initiation.