Through years, medicinal plants have always been used, but during the last century, their importance has increasingly grown. It should be emphasized that plants produce different substances, primary metabolites with the aim of helping life's cells and secondary metabolites, also known as phytochemicals, which have biological effects. The hardest part is treating plants, as complex matrices in general, and it's one of the most interesting challenges for analytical chemists. To this end, it is necessary to highlight how the need for standardization for plant extracts is of fundamental importance in the various sectors since only in this way will it be possible to effectively correlate the observed biological activity with a specific chemical profile and/or with the presence (especially based on its quantity) of one or more specific compounds. In this chapter, we want to bring to the reader's attention the main extraction procedures applied nowadays, how these can influence the chemical profile of the extract, and above all, bring to light an element that is becoming increasingly important, i.e., the development of green procedures through the application of the principles of both Green Analytical Chemistry (GAC) and Green Sample Preparation (GSP).
