Diabetes mellitus is a disorder characterized by the presence of excess glucose in the blood and tissues of the body. The word “diabetes” comes from the Greek for “a siphon,” referring to the discharge of an excess quantity of urine; the word “mellitus” comes from Latin for “honey.” Thus, diabetes mellitus refers to the passage of large amounts of sweet urine. Diabetes is a disease in which the pancreatic hormone insulin is either not produced or not properly used by the body. It is characterized as a chronic metabolic disorder with hyperglycemia (high blood sugar) and abnormal energy metabolism. Diabetes is caused by a combination of genetic, autoimmune, and environmental factors.