Diabetes mellitus is a chronic endocrine disease characterized by a persistent increase in blood glucose levels (hyperglycemia) due to a deficiency of insulin or a violation of its interaction with cells. The main symptoms include constant thirst, dry mouth, frequent urination, weakness, and prolonged wound healing. The main types are 1 (lack of insulin) and 2 (insulin resistance). The disease requires constant monitoring of nutrition and treatment to prevent severe complications.