Abstract: The present study was done to test the effect of Pb treatments on secretory tissue and the chemical structure of
the essential oils of basil (Ocimumbasilicum L.). Lead treatments were as follow: 100, 250, 500 and 7500 ppm in addition
to control. The experiment was done on Ocimumbasilicum L. in a greenhouse, arranged as a randomized complete block
design with three replications for each treatment for 60 days.The morphological structure of the secretory tissue of basil
leaves was investigated, using SEM (sca nning electron microscope).The chemical composition of natural products of sweet
basil exposed to lead treatments extracted by methanol and n-hexane, was analyzed by gas chromatography coupled with
mass spectrometry (GC–MS). The Results revealed the presence of organic aldehyde, diterpenes, monoterpenes, and
phenolic compounds in addition to unknown substances. Compounds in the hexane fraction included camphor, 1,8 -Cineol,
L-,alpha-Terpeniol, Eugenol, Methyl Eugenol, Beta Elemene, Pachoulene, gamma Cadinene, 9,12,15-octadecatrienoic
acid,methyl ester, Delta Cadinene, Linolenic acid β- cadinene,stearic acid, and an unknown substances . Compounds in the
methanol fraction included furfural, 1,8-Cineol, 4H-pyran-4-one,2,3-dihydro-3,5-dihydroxy-6-methyl, trans geraniol, β-Linalool,L-,alpha-Terpeniol, Alpha-Fenchyl acetate, Eugenol, Methyl Eugenol, 9,12,15-octadecatrienoic acid, methyl
ester, gamma Cadinene, Linolenic acid, β-elemene, bicycle[3.1.1]hept-2-ene,2,6-dimethyl-6-[4-methyl-3-pentenyl]- and
unknown substances. Results were concluded that Ocimumbasilicum is tolerant to lead treatments until 200 ppm, so it can
be used as alternative crops for Pb enriched soils