Ocimum basilicum is a common herb that is known for its ornamental and therapeutic importance. The chemical constituents which have been isolated from the plant include terpenoids, alkaloids, flavonoids, tannins, saponin glycosides and ascorbic acid. It has been reported to be hepatoprotective, immunomodulatory, antihyperglycemic, hypolipidemic, antitoxic, anti-inflammatory, antibacterial and antifungal. The present review is aimed to cover the phytochemical study and pharmacological investigations on this important medicinal herb.