abstract the essential oils of thymus pallescens de no'e and origanum floribundum munby leaves and flowers were analyzed by gc and gc/ms. the oil yields of t. pallescens were 2.8% for the leaves and 3.7% for the flowers, while those of o. floribundum were 2.0% for the leaves and 5.4% for the inflorescences. the major constituents of both the leaves and flowers of t. pallescens were p-cymene (17.4% and 9.2%), -terpinene (10.6% and 14.1%) and carvacrol (39.0% and 48.3%), respectively, while those of o. floribundum were p-cymene (22.3% and 9.6%), -terpinene (17.3% and 24.3%) and thymol (34.4% and 41.2%), respectively. for the both plants p-cymene and sesquiterpenes were essentially concentrated in leaves. key word index: thymus pallescens origanum floribundum lamiaceaeessential oil compositioncarvacrolp-cymene-terpinene