Holy basil commonly known as or tulsi, is an aromatic perennial plant in the family Lamiaceae. It is native to the Indian subcontinent and widespread as a cultivated plant throughout the Southeast Asian tropics.
Holy basil (Ocimum sanctum) is a widely grown, sacred plant of India. Hindus grow Tulsi as a religious plant in their homes, temples and their farms. They use Tulsi leaves in routine worship. Tulsi, grown as a pot plant, is found in almost every traditional Hindu house. The natural habitat of Tulsi varies from sea level to an altitude of 2000 m. It is found growing naturally in moist soil nearly all over the globe. Tulsi is a branched, fragrant and erect herb having hair all over. It attains a height of about 75 to 90 cm when mature. Its leaves are nearly round and up to 5 cm long with the margin being entire or toothed. These are aromatic because of the presence of a kind of scented oil in them. A variety with green leaves is called Shri Tulsi and one with reddish leaves is called Krishna Tulsi. Tulsi flowers are small having purple to reddish color, present in small compact clusters on cylindrical spikes. Stalkless heart-shaped bracts are there at the base of each flower cluster. Sepal cup is not hairy within. Flowers are rarerly longer than 5 mm, calyx tube bearded outside near base. Flower tube is hairy. The fruits are small and the seeds yellow to reddish in color.
Because of its medicinal virtues, Tulsi is used in Ayurvedic preparations for treating various ailments. It has been used in Ayurveda and Siddha practices for its supposed treatment of diseases. For centuries, the dried leaves have been mixed with stored grains to repel insects. Its use is recommended as a first aid in the treatment of respiratory, digestive and skin diseases. Apart from these common ailments, Ayurveda also recognizes its use for the diseases ranging up to tumerous growths. Experimental studies identify it to be a highly promising immunomodulator, cytoprotective and anticancer agent.