The fractionation work of the aerial parts of Senecio atacamensis Phil. afforded, in addition to the already known 6beta -hydroxyeremophilenolide, a new sesquiterpene lactone 6beta - hydroxy - 8alpha - methoxyeremophil -1(10),7(11) - dien - 8beta,12 olide. The structures were established by spectral data, in particular 2D NMR (DEPT, DQF-COSY, HMQC, HMBC and ROESY).