Ashwagandha is a small evergreen shrub. It grows in India, the Middle East, and parts of Africa. The root and berry are used to make medicine.
Ashwagandha is commonly used for stress. It is also used as an "adaptogen" for many other conditions, but there is no good scientific evidence to support these other uses.
Don't confuse ashwagandha with Physalis alkekengi. Both are known as winter cherry. Also, don't confuse ashwagandha with American ginseng, Panax ginseng, or eleuthero.