The diabetes mellitus is a metabolic disorder of several etiologies that share the phenotype of increased high blood glucose level (hyperglycaemia). It is characterized by chronic hyperglycaemia with impaired metabolism of carbohydrate, fat and protein caused due to defects in insulin secretion, utilization of glucose, glucose production etc. The long-term effect of diabetes mellitus causes secondary pathophysiologic changes in various organs that damages, dysfunction and causes failure of organs. Association of Diabetes Mellitus with dysregulation in metabolism causes secondary pathophysiologic changes in various organs that impose a tremendous burden on the individual with diabetes and on the health care system. It leads to cause of end-stage renal disease (ESRD), nontraumatic lower extremity amputations, and adult blindness. It also predisposes to cardiovascular diseases. With an increasing incidence worldwide, DM will be a leading cause of morbidity and mortality for the foreseeable future.

Diabetes mellitus show characteristic symptoms such as thirst, polyuria, blurring of vision, and weight loss. In its most severe cases DM may develop, ketoacidosis or a non-ketotic hyperosmolar state that leads to state of unconsciousness, coma and, if not treated at this stage causes, death. Often symptoms are unnoticed, not severe, or may be absent, and consequently DM causes pathological and functional changes before it is been diagnosed. Increased number of prevalence of DM in the developing countries is predominantly associated with change in life style and obesity. Increase in understanding of pathogenesis of DM and its complications and in prevention and therapy of DM are critical to meeting this challenge.

Diabetes malitus is broadly classied as Type-1, Type-2 and gestational diabetes. Type- 1 is caused due to lack of ability to produce Insulin that results from complete destruction of insulin-producing beta cells in the pancreas or in ability to produce insulin. Patient with type 1 DM needs to be supplemented with insulin. Type 1 DM is fatal if left untreated. Gestational diabetes is found in non- diabetic women usually during their third trimester of pregnancy. Gestational diabetes needs treatment, and usually disappear after delivery. But in some cases gestational diabetes may lead to type-2 diabetes later. Type 2 diabetes is characterized by high blood sugar in the context of insulin resistance and relative lack of insulin. Type 2 diabetes can initially be controlled by exercises and proper diet. In chronic type 2 diabetes if cannot be controlled by exercise and diet, medications should be started. If Type 2 diabetes is left untreated it may end up fatal.