The “Entourage Effect” is the term used to describe the enhancement of therapeutic effectiveness of cannabis from the synergistic combination of cannabinoids, terpenes, flavonoids and fatty acids working in tandem. In other words, the entourage effect is the advantage you get from consuming the plethora of naturally occurring chemicals in the cannabis plant together, rather than only ingesting isolated THC and/or CBD.
Raphael Mechoulam and Shimon Ben-Shabat, the first two scientists to describe isolated CBD, discovered this effect in 1998. With a variety of components working together as an entourage, the duo noted that “This type of synergism may play a role in the widely held (but not experimentally based) view that in some cases plants are better drugs than the natural products isolated from them”.
Considerable research has been done on this interaction since the late 1990s. Further support for this theory has been garnered from studies demonstrating the increased therapeutic effects (2 to 4 times greater) of cannabis extract over pure THC, from increased anticonvulsant activity to “inhibitory activities about 10 times that of aspirin.” Additionally, neurologist and psychopharmacology researcher Ethan Russo described interactions between terpenes and cannabinoids to counter a variety of conditions, including inflammation, pain, epilepsy, depression, and cancer.
Aside from the purported therapeutic value, recent research has proposed that the synergistic influence of the chemicals can also counter the less desired effects of cannabis - such as THC-induced anxiety. As we know, THC and CBD have a reported inverse effect, the presence of CBD will reduce the psychoactive properties of THC. The entourage effect is one of the main factors for why many consider full and broad-spectrum CBD oil to be superior in therapeutic value to CBD isolate. Consumers are consistently becoming more knowledgeable about CBD related products and we've already seen an increase in full-spectrum products.
 NCBI Article 1
 NCBI Article 2