Background: Hydatid disease, a parasitic infestation of humans, is endemic in the Mediterranean region, Australia, New Zealand and the Middle East, and mostly involves the liver. Anaphylactic reactions, which sometimes are the first manifestations of the disease, frequently occur due to cyst rupture after a minor/major trauma, though they may also be spontaneously seen on rare occasions. In extremely few studies, anaphylactic shock has been reported in patients without macroscopic rupture of the hydatid cysts. Case Report: Our patient had recurrent anaphylactic episodes without any trauma and had been misdiagnosed for several years even though the patient was living in a region endemic for hydatid disease. Conclusion: We emphasize that physicians should be highly aware of hydatid disease as a possible etiology for seemingly idiopathic anaphylactic reactions, especially in endemic regions. Copyright (C) 2007 S. Karger AG, Basel.