In this study, we were interested in the valuation of Ocimum gratissimum, an aromatic and medicinal plant of the Ivorian flora. The essential oils of the leafy branches of Ocimum gratissimum were extracted by hydrodistillation with a Clévenger-type device. The yield of the oils obtained increases from (0.05±0.01%) to (0.42±0.08%) depending on the drying time. The density of essential oils is almost constant at 0.80. The chemical composition of essential oils was identified after analysis of chromatograms and mass spectra. The number of phytocompounds also increases with the number of drying days from 32 to 37. These compounds are marked by the presence of hydrocarbon monoterpenes from (29.11% to 49.1%), and oxygenated from (40.33% to 50.02%) and the presence of hydrocarbon sesquiterpenes from (5.52% to 8.55%), and oxygenated from (0.80% to 2.16%). The number of major compounds is 5 on day 0 and decreases to 4 on the other days, and have the following proportions: thymol from (33.60% to 44.73%), β‑caryophyllene from (2.54% to 3.29%), para-cymene (12.32% to 25.60%), γ-terpinene (10.09% to 11.41%), Bis(2-ethylhexyl)phthalate (12.12% to 0.42%). bis (2-ethylhexyl) phthalate which is in the minority during the other drying days.