Hydatid disease is a parasitic tapeworm infestation. Anaphylactic reactions as a result of cyst perforation generally occur after trauma during a spread of cystic fluid in the intravascular space, which may also initiate anaphylaxis. The reported case was a 17-year-old boy who was admitted to the hospital emergency department with a sudden onset of nausea, vomiting and fainting, resulting in death. The cause of his sudden death was unknown. Autopsy macroscopically revealed hydatid cysts in the liver. In the histopathological examination, hydatid cyst was recognized by scolices and also an inflammatory infiltration composed mainly of mast cells in the myocardium was detected. Sudden death in this case was attributed to allergic myocardial infarction due to intravascular spread of the hydatid cyst content (Fig. 2, Ref. 10).