Diabetes mellitus (from the Greek, meaning “siphon” or “to pass through,” and meli, meaning “honey”) is a disorder of the metabolism caused when the pancreas either produces little or no insulin, or when the cells do not respond appropriately to the insulin that is produced. Glucose builds up in the blood, overflows into the urine, and passes out of the body. As a result, the body does not benefit from glucose as a source of energy.