BACKGROUND There are several scolicidal agents for inactivation of hydatid cyst protoscolices during surgery, but most of them are associated with adverse side effects such as sclerosing cholangitis (SC) and liver necrosis. The present study aimed to evaluate the adverse effects of Eucalyptus essential oil to induce SC in animal models. METHODS Eighteen rabbits weighting 2000-3500 g were included in three groups for this study. About 0.3 ml of Eucalyptus essential oil (1%), or 5% hypertonic saline, or normal saline was injected for 5 min in the gallbladder. After 4 months, the liver, common bile duct, and duodenum were resected and immediately sent for cholangiography and pathologic studies. RESULTS According to pathological studies, inflammation is more common in Eucalyptus and hypertonic saline groups. Due to cholangiographic studies, stricture was slightly higher in the hypertonic saline group than the Eucalyptus group. CONCLUSIONS Thus, 1% Eucalyptus essential oil is at least as safe as 5% hypertonic saline, but for clinical uses, it must be confirmed with further studies.