Winter cherry (withania somnifera), also known as ashwagandha or Indian ginseng, has traditionally been used as part of a holistic system of medicine in India known as ayurveda. The herbal supplement is produced from the root of the plant and is known as an adaptogen, meaning that it increases resistance to physical and emotional stress. In terms of emotional health, winter cherry has been used to promote emotional balance in cases of mild anxiety, depression and mental or physical fatigue. The supplement is also known to have many preventative qualities, such as anti-inflammatory and antioxidant properties.

More Info: http://en.wikipedia.org/wiki/Withania_somnifera