Ashwagandha

Ashwagandha is one of the premier tonic herbs in Aryuvedic and Unani medicine.

Considered a Rasayana or restorative herb in Aryuvedic medicine, it is used for a wide variety of chronic health conditions. In the West it has become an extremely popular herb for it's adaptogenic and nerve soothing properties. For the practitioner of TCM, it's actions could be considered to Tonify the Yin, Yang, and Qi of the Kidney, Nourish Heart Blood and Calm the Spirit, Tonify Heart Qi, and Dispel Wind and Damp.

Ashwagandha is an incredible herb to use as a single or added to formulas especially when there is chronic deficiency that is coupled with feelings of anxiousness and/or difficulty sleeping. A way to understand this action could be to compare it to the formula Tian Wang Bu Xin Dan (Celestial Emperor's Blend). Ashwagandha is less sticky/cloying, more tonifying to the kidney Qi and Yang, and less sedating. Tian Wang Bu Xin Dan is more tonifying to the Blood and Yin aspects.

Compare it with Ren Shen (Chinese Red Ginseng). Both are powerful, broadly acting, warming tonics that support long term vitality. Ren Shen can be more stimulating and has more Spleen tonifying properties. Ashwagandha has stronger Calm Spirit actions, is more settling and has the ability to Dispel Wind and Damp.   

Some of Ashwagandha's actions are also comparable to an herb like Ba Ji Tian (Morinda root). Both herbs are Warming, and Tonifying of the Kidney Yang, yet have moistening and blood tonifying actions.  Both have some dispersing nature and are used for chronic painful obstruction with Kidney deficiency. Unlike Bai Ji Tian, Ashwagandha has influence on the Heart and Calms the Spirit. Ashwagandha is also  perhaps more Tonifying and less Dispersing of Wind Damp Cold than Ba Ji Tian.