This module aims to provide an understanding of the major classifications of plant constituents, their basic molecular structure, known pharmacology, and relevance in regards to the use of herbs in a clinical setting. This module also serves to recognize the advantages and disadvantages of using a whole plant vs. isolated constituent extract, and understand the concept of synergy in relation to a plant’s constituent profile. Additionally, this module creates an understanding of how a plant’s primary active constituent(s) will contribute towards its pharmacology, mechanism of action and potential therapeutic applications. Lastly, this module gives examples of herbs that are rich in a given constituent, and their relevance in a clinical setting.