compositional characteristics of the essential oils of four ocimum spp., namely ocimum adscendens willd., ocimum gratissimum l., ocimum tenuiflorum l. and ocimum americanum l. were examined using gc-fid, gc-ms, and hierarchical cluster analyses from peninsular india. the essential oil content varied from 1.0% to 2.0% in different ocimum spp. altogether eighty-four constituents, corresponding to 89.9-96.5% of the total oil compositions were identified. major constituents of o. adscendens oil were eugenol (47.6%), (e)-caryophyllene (15.7%) and -elemene (11.3%). o. gratissimum oil was characterized by the presence of higher amounts of eugenol (52.9%), caryophyllene oxide (7.2%) and (z)--ocimene (3.5%). major constituents of o. tenuiflorum oil were methyl eugenol (50.9%), caryophyllene oxide (7.5%) and (e)-caryophyllene (5.5%). moreover, the oil of o. americanum was dominated by camphor (41.8%), limonene (7.1%), -pinene (6.2%), -selinene (5.6%) and camphene (5.0%). to the best of our knowledge, a detailed essential oil profile of o. adscendens is being reported for the first time.