abstract the composition and the antimicrobial activity of the essential oil of luma chequen from peru were investigated. essential oil was analyzed by gc and gc/ms. the oil was characterized by the presence of small amounts of sesquiterpenes (3.1%), and large amounts of monoterpenes (90.1%), of which -pinene (57.1%), 1,8-cineole (12.1%) and linalool (5.5%) were the major compounds. the oil showed significant antimicrobial activity against proteus vulgaris, cryptococcus neoformans and cladosporium cladosporioides, with mic values ranging from 0.45 to 1.67 l/ml.