The National Registry of Drug-induced Ocular Side Effects has accumulated 13 cases of possible major haemopoietic responses from topical ocular chloramphenicol. Over 75 cases of major haemopoietic events from carbonic anhydrase inhibitors are also reviewed. While numerous reports of local ocular effects secondary to timolol have been received by the Registry, the more significant adverse effects are the same systemic side effects seen with any beta-receptor blocking agent. Data in the Registry have shown that allopurinol may be possibly associated with cataract formation. Severe cardiovascular effects with elevated blood pressure and stroke are uncommon systemic adverse reactions following topical ophthalmic 10% phenylephrine, but these systemic effects have also been seen secondary to concentrations of 2.5%. Other drugs, such as adrenaline (epinephrine), ecothiopate (echothiophate), practolol, thiabendazole, and penicillamine are suspected of causing ocular pseudopemphigoid.