Herbal Supplement Approved by Michael Tierra L.Ac, O.M.D Ashwagandha (Withania somnifera) is one of the most highly respected botanicals in the 5,000-year-old Ayurvedic herbal tradition of India. Classified as a rejuvenative tonic ("rasayana") in the Ayurvedic system, it is widely used in modern Western herbalism as an adaptogen - a substance that can help our bodies healthfully adapt to physiological and psychological stress, thus increasing our resistance to stressors.