Karunthulasi also called as Black Basil is a well known plant in India, famous for its medicinal values and intensity over ordinary Holy Basil. Karunthulasi entire plant including leaves, stems are collected, dried well, ground into very fine powder. It is then filtered to make it free from unground particles. It is being used by our ancestors along with Tea to maintain good respiratory health. 

It is called as Black Basil in English. Rama Thulasi or Krishna Thulasi is its name in almost all the Indian Languages including Tamil, Malayalam, Kannada, Telugu, Marathi, Hindi, Gujarathi, Rajasthani, Oriya. Its Botanical Name is Ocimum Tenuiflorum and Ocimum Sanctum.

Disclaimer: Before taking any herbal as an intake, you are requested to consult with a Siddha or Ayurveda Doctor or any other Traditional Siddha Physician to avoid further health related problems. They will help you to understand the procedure, the effect of other herbals and foods to avoid if any, upon consuming the herbs.