AbstractComplications from mydriatic and cycloplegic drugs are rare compared with their extensive use. Adverse effects are often related to dosage or other factors. The ocular complications include increased intraocular pressure, pigmentation of the conjunctiva and cornea, pigment in the anterior chamber, lacrimal duct blockage, macular edema, corneal endothelium damage, hyperemia, allergy, discomfort, and blurred vision. The systemic complications are those common to sympathomimetic and parasympatholytic drugs and include tachycardia, hypertension, headache, faintness, pallor, trembling, excessive sweating, palpitations, arrhythmias, confusion, hallucinations, drowsiness, ataxia, flushed skin, high fever, dysarthria, thirst, dry mouth, convulsions, disorientation, nervousness, coma, and death. An understanding of all possible side effects is of paramount importance to those using these drugs in the treatment of anticholinesterase poisoning. This review is intended as a ready reference to the adverse effects of mydriatic and cycloplegic drugs.