Full-spectrum extracts, often called whole plant extracts, maintain the full profile of the cannabis plant. They contain a variety of cannabinoids, including THC, THCa, CBD, CBDa, CBG, and CBN, as well as terpenes and other compounds such as flavonoids, proteins, phenols, sterols, and esters.
These extracts are desirable for several reasons. From an experiential standpoint, they replicate the flavor and aroma profile of the plant. From a therapeutic or medicinal standpoint, you get the full benefits of the entourage effect—the theory that the various components of the plant work synergistically to enhance the action of the active substances, such as THC and CBD.
Full-spectrum extracts are notoriously difficult to produce. While you need to keep as many of the desirable compounds as possible, you also want to rid the extract of unnecessary components. Some extraction methods filter the latter out using a variety of refinement techniques.