Considering that it's a root, how much antioxidants there are in ashwagandha is extremely high. While not as high as raw ginger root, its ORAC is greater than garlic, carrots, and all types of onions.
In India, the Withania somnifera root has been prized by Ayurvedic medicine for centuries, possibly even millennia. Historically, the ashwagandha was ground up into a fine powder to make an herbal tea, which included milk and honey. In Western cultures, the benefits of ashwagandha are often realized using supplements instead.
Research Support, Non-U.S. Gov't: The Journal of Alternative and Complementary Medicine. Volume 13, Issue 1. NIH 2007