Hydatid disease, caused by the cestode Echinococcus granulosus, is common in Mediterranean regions, being highly endemic in Greece. Depending on its size, an intact hydatid cyst may be "silent" or may cause symptoms from compression of adjacent organs. Rupture of a hydatid cyst commonly gives to allergic phenomena, which can include anaphylactic shock. A case is presented in which there was a two-year history of recurrent anaphylactic shock due to small, incomplete ruptures of hydatid cyst. The case emphasizes the potentially life-saving importance of early diagnosis of hydatid cyst.