Cystic echinococcosis, caused by helminths within the genus Echinococcus, is mainly localised in the liver and lungs of affected hosts. Surgery has been the best choice for the treatment of hydatidosis and using effective scolicidal agents during hydatid surgery is required to prevent secondary infection. Several plant extracts have been shown to exert scolicidal efficacy. This study was designed to investigate the in vitro scolicidal activity of methanol extract of Sideritis perfoliata against the protoscolices of hydatid cysts.The protoscolices were collected from a liver of a sheep slaughtered in Adiyaman city slaughter, Turkey. Three concentrations of the aerial part extract of S perfoliata (0.1, 0.2 and 0.4 mg/mL) were assessed at three different exposure periods. All tests were carried in duplicate. The viability of protoscolices was assessed by the eosin exclusion test (0.1% eosin staining).Scolicidal effect of S perfoliata extract at exposure periods of 10, 20 and 30 minutes was 29.6%, 32.5% and 43.6% at the concentration of 0.1%, 37.8%, 50% and 58.1% at concentration of 0.2 mg/mL, and 57.9%, 71.8% and 79.1% at the concentration of 0.4 mg/mL, respectively; indicating a longer time is required to display protoscolicidal effects. LC-MS/MS analysis showed that some phenolic acids, such as fumaric acid (260.13 mg/L), syringic acid (27.92 mg/L) and caffeic acid (26.84 mg/L), and a flavonoid, luteolin (11.23 mg/L) were detected in high concentrations in the extract.This study has demonstrated that the methanol extract of S perfoliata has high scolicidal activity in vitro. However, research on the in vivo efficacy of S perfoliata extract and its potential side effects is required.