We describe a patient who developed acute angle-closure glaucoma following the application of topical intranasal cocaine. A 46-year-old woman underwent an elective antral washout under general anaesthesia and with local application of 25 per cent cocaine paste to the nasal mucosa. Twenty-four hours post-operatively the patient developed sudden painful blindness which was found to be due to acute glaucoma. Cocaine with its indirect sympathomimetic activity causes mydriasis, that can precipitate acute angle-closure glaucoma in predisposed individuals with a shallow anterior chamber. Although the incidence is rare, otolaryngologists need to be aware of this potential complication.