Mydricaine is a mydriatic agent used routinely at the Royal Adelaide Hospital in subconjunctival injections that are given prior to all vitreoretinal surgery. The drug is manufactured by the hospital pharmacy and each vial of 0.4 mL mydricaine number 02 consists of a mixture of 1.3 mg atropine sulphate, 0.12 mg adrenaline and 8.4 mg procaine hydrochloride. Mydricaine is routinely used by many vitreoretinal units, even though the drug is not listed in the British National Formulary (BNF) or Monthly Index of Medical Specialities (MIMS). Therefore, published case reports provide the main forum for reporting side-effects. The case presented is of a patient with no previous ischaemic heart disease who developed transient myocardial ischaemia with tachycardia following the administration of subconjunctival mydricaine number 02. To the authors’ knowledge this is the first case report documenting myocardial ischaemia in a patient with no previous ischaemic heart disease following mydricaine administration.