Ocimum sanctum Linn., also referred to as Holy Basil or Tulsi, is a Southeast Asian Ayurvedic plant with a long history of conventional use. The significance of this plant for use in food, medicine, and industry prompted researchers to examine its chemistry and pharmacology. Over 60 chemical substances, including phenolics, flavonoids, phenyl propanoids, terpenoids, fatty acid derivatives, essential oil, fixed oil, & steroids have been identified in O. sanctum. According to the study, tulsi leaf extract contains a number of secondary metabolites, including glucose, tannin, flavonoids, saponins, glycosides, terpenoids, fatty acids, and phenol. Its anti-inflammatory, analgesic, antipyretic, antidiabetic, hepatoprotective, hypolipidemic, antistress, & immunomodulatory properties have been demonstrated by scientific investigations. Preclinical research has also demonstrated that tulsi and some of its phytochemicals, including eugenol, rosmarinic acid, apigenin, myretenal, luteolin, -sitosterol, and carnosic acid, prevented cancers of the skin, liver, mouth, and lung caused by chemicals. These effects were mediated by a rise in antioxidant activity, changes in gene expression, induction of apoptosis, and inhibition of angio. It has been demonstrated that Tulsi's aqueous extract and the flavonoids orientin and vicenin in it shield mice from radiation-induced disease and mortality while protecting normal tissues just from the tumor-crushing effects of radiation.