cystic echinococcosis remains a serious public health problem worldwide. surgery is considered as the first option of treatment. various investigations were carried out to find a convenient scolicidal agent for reducing the risk of post-surgical recurrence of the disease but most of them are associated with adverse side effects. the present study aimed to evaluate the in vitro scolicidal activity of thymus capitatus hoff. et link. essential oil against echinococcus granulosus protoscoleces. three concentrations of essential oil (1, 2 and 3 mg/ml) were tested for 1 to 10 min on e. granulosus protosoleces and their viability was assessed by eosin staining test. the essential oil concentrated at 2 and 3 mg/ml killed 100% protoscoleces after 5 and 1 min, respectively. furthermore, gc/ms and gc-fid analyzes indicated that carvacrol (82.4%) was the major component of the essential oil. the current investigation showed the potent scolicidal effect of t. capitatus essential oil in vitro.