An active plant constituent that binds proteins through an astringent action; originally derived from plants used for tanning leather.

A somewhat straight tapering root that grows vertically downward.

The science of classifying living organisms by assigning each organism to a category depending on the degree of similarities or relatedness to another.

Complex active plant constituents with a carbon ring structure, generally highly aromatic and often a component of essential oils.

A concentrated herbal extract made by macerating herbs in alcohol and water.

An herb that strengthens the body through a general tonifying effect or through specific affinities for certain organs.

A swollen part of an underground plant stem, capable of new growth.