Not only from religious point of view but from medicinal perspective too it is highly useful. The mere smell of leaf makes the atmosphere healthy and hinders the growth of mosquitoes and flies in the area.
There are mainly two types of tulsi:
Shyam tulsi: With dark coloured stems and leaves
Rama tulsi: Whitish stems and green leaves
Both types are approximately same as far as qualities and smell is concerned. Yet Shyam tulsi is considered more useful than Rama tulsi.
Those who eat five leaves of tulsi daily remain protected from different types of diseases with enhanced memory power and intelligence. Old people do not experience weakness and remain protected from several chronic diseases.
Basil leaves are blood purifier. It enhances the beauty naturally. From medication purview it is not just a medicine but a super-medicine(maha aushadhi).
In Ayurveda it is considered as the destroyer of all the three doshas.
Taking juice of basil leaves with water on empty stomach in the morning increases the glow and memory power. It enhances digestive power as well. This is kriminaashak. Basil juice immediately stops vomitting. Its juice is very helpful in malaria. It enhances the functioning of kidneys and is very helpful in case of acidity, piles, white spots on skin, obesity etc. Fever, cough, prakay, and TB patients are benefited by taking three grams of tulsi every day. Basil juice with honey should be given for six months to patients suffering from stone problem. Cough, cold, fever, diarrhoea and vomiting etc. can be cured by tulsi. Its juice controls blood cholesterol level.