The endocannabinoid system (ECS) is made up of cannabinoid receptors and corresponding endocannabinoids. Endocannabinoids are produced by the body and fit exactly into the endocannabinoid receptors, much like a lock and key. The body’s cannabinoid receptors also interact with exogenous ligands and phytocannabinoids, which are found in both plants and synthetic cannabinoids. These exogenous cannabinoids may have different or stronger effects on the receptors than endogenous cannabinoids, but ultimately they are working with the same locks.