Holy Basil, Tulsi
Holy basil, closely related to the plant you make pesto or toss over tomatoes, is a very potent medicinal herb. It could be called an anti-everything herb, the uses include: anti- strees, anti-microbial, anti-diabetic, anti-fungal, anti-inflammatory, antioxidant and anti-ulcer in short words a herbal must-have panacea. It has been proven to be very safe evn in long term use.
Unfortunately, despite being perennial, holy basil is frost sensitive.