Life-threatening anaphylaxis is a systemic hypersensitivity reaction that may be allergic or non-allergic. Kounis syndrome is an acute coronary syndrome caused by an allergic reaction. Food, environmental factors, drugs, radiological contrast agents and some disease states are among the etiological factors that trigger an allergic reaction. Kounis syndrome is a relatively rarely recognized cause of myocardial infarction, which is most likely due to its underdiagnosis. The presented case concerns a patient with a history of ischemic heart disease after coronary angioplasty. Until the insect stings, the course of the angina was stable. The course of the allergic reaction was turbulent and met the criteria for anaphylactic shock. Subsequently, the patient developed unstable angina. The clinical picture and additional tests allowed to diagnose a myocardial infarction in the patient. The coincidence of myocardial infarction with a history of an insect sting allows for the recognition of an allergic reaction as a trigger for acute coronary syndrome. The described case highlights the need for a multidisciplinary approach to the patient and regular supervision during the use of specific immunotherapy in the course of allergy to Hymenoptera venom, as well as the inclusion of Kounis syndrome in the differential diagnosis of acute coronary syndromes.