The hexane extract of aerial parts of Santolina rosmarinifolia subsp. canecens afforded eight new sesquiterpenes in addition to known compounds. Their structures were determined by spestroscopic methods and chemical transformations. The conformational analisys of the germacrane constituents was carried out by spectroscopic methods, including NMR at varying temperature and by molecular mechanics calculations. The antifeedant, antibacterial and antitumoral activity of selected compounds has been tested.