GCMS ONE OF THE BEST METHODS FOR CHEMICAL COMPOSITION ANALYZES OF THE PLANTS ESSENTIAL OIL AND VOLATILE EXTRACTS.THYMUS SPECIES ARE WELL KNOWN AS MEDICINAL PLANTS BECAUSE OF THEIR BIOLOGICAL AND PHARMACOLOGICAL PROPERTIES.THE GENUS THYMUS L., KNOWN AS ‘‘AVISHAN” IN PERSIAN, IS A WELLKNOWN AROMATIC PERENNIAL HERB ORIGINATED FROM MEDITERRANEAN REGION.AMONG 215 SPECIES OF THIS GENUS GROWN IN THE WORLD, 14 SPECIESARE DISTRIBUTED IN IRANIAN FLORA [1, 2].THE AIM OF THIS RESEARCH WAS TO STUDYTHE ESSENTIAL OIL COMPOSITION OF Anisosciadium ORIENTALE SPECIE OF THE GENUS UMBELLIFERAE BY GCMASS ANALYZE. ...