Holy basil, closely related to the plant you make pesto or toss over tomatos, 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.
Don't confuse it with Thai basil which is a variety of Ocimum basilicum.