Some herbs preserve all their medicinal properties in their roots. Many different herbs are harvested for their root only.
Ramacham (vetiver -Chrysopogon zizanoides) is a grass herb, the root of which is used for different medicinal purposes and for keeping potable water fresh and cold. The mat made from the root of the plant, watered and placed across the window cools the incoming wind and the people inside gets finer experience than being in the best air-conditioned room.
The root of (Aswagandha) Withania Somnifera root has many properties including action against cancer cell growth, anxiety, stress, heart problems, thyroid problems etc.
Herbal roots are extremely powerful and used for the directed purposes only. In fact almost all medical preparations utilize one or more herbal roots.