Objective:To perform phytochemical analyses on the leaves of Ocimum basilicum L.(O.basilicum),to elucidate the structure of isolate and then perform the antisickling activity on the crude extract and on the isolate.Methods:The Emmel test performed on the acidified methanolic extract of this plant was used to evaluate the antisickling activity.The structure characterization of the active compound was performed using chromatographic techniques for the separation and the spectroscopic ones for structure elucidation(1H-NMR,13C-NMR.COSY,HMBC).Resurte:The chemical screening on the crude extract revealed the presence of polyphenols(flavonoids,anthocyanins,leucoanthocyanins,tannins,quinones) alkaloids,saponins,triterpenoids and steroids.The ohtained extract after evaporation yielded 34.50g(11.5%) out of 300g of powdered leaves of O.basilicum.The acidified methanolic extract and butyl stearate showed an interesting antisickling activity.Conchisions:The acidified methanolic extract and butyl stearate from O.basilicum displayed a good antisickling activity.To the best of our knowledge,this is the first time to report the antisickling activity of this compound in this plant.The synmesized compound presented the same spectroscopic characteristics than the natural one and the antisickling activities of its derivatives are understudying. Objective: To perform phytochemical analyzes on the leaves of Ocimum basilicum L. (O.basilicum), to elucidate the structure of isolate and then perform the antisickling activity on the crude extract and on the isolate. Methods: The Emmel test performed on the acidified methanolic extract of this plant was used to evaluate the antisickling activity. The structure characterization of the active compound was performed using chromatographic techniques for the separation and the spectroscopic ones for structure elucidation (1H-NMR, 13C-NMR.COSY, HMBC) : The Chemical screening on the crude extract revealed the presence of polyphenols (flavonoids, anthocyanins, leucoanthocyanins, tannins, quinones) alkaloids, saponins, triterpenoids and steroids. The ohtained extract after evaporation yielded 34.50g (11.5%) out of 300g of powdered leaves of O.basilicum.The acidified methanolic extract and butyl stearate showed an interesting antisickling activity. Confchisions: The acidified methanolic extract and butyl ste arate from O.basilicum displayed a good antisickling activity.To the best of our knowledge, this is the first time to report the antisickling activity of this compound in this plant. synsylated compound presented the same spectroscopic characteristics than the natural one and the antisickling activities of its derivatives are understudying.