Called basil in English, the name of this plant literally means "matchless". The tulasi is believed to be Lakshmi`s incarnation on earth . .
The tulasi is revered for its medicinal properties as well as its spiritual value The leaves are a remedy for coughs, and if eaten after meals, assist digestion. They are also put in cooked food and in stored water to prevent them from spoiling. The tulasi is believed to be an antidote to snake venom. When burnt, its smoke repels insects. From this last quality came the social diktat that if tulasi branches are added to a funeral pyre, the soul of the dead would go to Vaikuntha. Practicality, this was done to keep flies and insects at bay until the funeral was over, to prevent the spread of disease from a possibly infected corpse. The tulasi plant is believed to be so pure that the slightest pollution can kill it. Therefore, women are not supposed to touch the tulasi plant while they are menstruating.
The most widely accepted legend about the origin of tulasi is in the Devi Bhagavata Purana. According to it, Vishnu had three wives: Sarasvati, Lakshmi and Ganga. Once Lakshmi and Sarasvati quarreled and cursed each other. Sarasvati`s curse turned Lakshmi into a tulasi plant and forced her to live on the earth forever .
In another version of the same story, after Sarasvati cursed Lakshmi to live on earth as tulasi, Vishnu explained that things had happened as predestined. Lakshmi would indeed be born so on earth and marry Shankhachuda, the demon, to help the gods vanquish him.
Accordingly, Lakshmi was born as Tulasi, and in due course was married to Shankhachuda. Because of a boon from Brahma, Shankhachuda could only be defeated if his wife was unfaithful to him. Believing he was invincible, Shankhachuda became arrogant and began tormenting people. They prayed to Vishnu for help, and Vishnu sent Shiva to kill Shankhachuda. Meanwhile Vishnu assumed the form of Shankhachuda and seduced Tulasi, to make her unfaithful and therefore nullify the effect of the boon. This would allow Shiva to kill the demon. When Tulasi discovered the deceit, she began to curse the impostor. Before she could complete the curse however, the imposter revealed himself to be Vishnu. He pacified Tulasi, and reminded her that she was, in fact, Lakshmi, who could now return to heaven with him since her curse was over. To mark the event, Lakshmi`s hair became the tulasi plant, which remained on earth and was worshipped thereafter as her image, and her body was transformed into the river Gandaki.
And so the tulasi is considered sacred. For the Vaishnavas in particular, no ceremony can be performed without it, and the worship of Vishnu is incomplete without its leaves. Since the tulasi and the Shalgrama Shila areso closely associated, every year in the month of Kartik, the Vaishnavas marry a tulasi plant to a shalgrama stone with great fanfare. It is believed that the tulasi ensures the presence of Brahma, Vishnu and Shiva, who are said to reside in it and of Lakshmi, Sarasvati and Gayatri who are believed to live in its flowering sprigs.
The tulasi is planted in the courtyards of many homes and is worshipped every day with water and pradakshina. This practice dates back to earlier times when entire families slept in the courtyard to escape the summer heat within the house. Since the tulasi emits oxygen and not carbon dioxide at night, unlike other plants, it was considered doubly effective to sleep in its sacred and healthy ambience.
"Tulasi" and its other name Brinda or Vrinda, are popular names for girls even today. It is frequently invoked in prayer and preaching as the embodiment of purity.