Modulation of endocannabinoid system (ECS) activity, which consists of CB1 and CB2 receptors, endocannabinoids, and their synthetic and metabolizing enzymes, may be beneficial in the treatment of many diseases such as inflammatory and cardiovascular diseases, diabetes, obesity, liver diseases, as well as in the amelioration of chemotherapy-related side effects and pain (Gyires and S. Zádori 2016). The gene discussed is CNR1; the disease is diabetes mellitus.