In the last decade topically applied prostaglandin F2alpha analogues (bimatoprost, latanoprost, travoprost and unoprostone) have become widely used as a means to reduce elevated intraocular pressure in patients with glaucoma and ocular hypertension. These molecules all have similar side-effect profiles, which include both side effects that occur frequently (e.g., conjunctiva hyperaemia, increase of iris pigmentation and eyelash changes) and rare adverse reactions (e.g., periocular pigmentation, damage to the blood-aqueous barrier and cystoid macular oedema). Conjunctiva hyperaemia, eyelash changes and cystoid macular oedema are reversible, but certain other side effects, such as increased iris pigmentation, are not. However, the systemic side-effect profile is favourable for all the prostaglandin analogues, and some of the local side effects are only of cosmetic significance. Numerous clinical studies suggest that discontinuing treatment with prostaglandin analogues on account of their side effects is rare in clinical practice.