Diabetes mellitus is characterized by high blood sugar levels and a tendency to develop complications. It is diagnosed through fasting blood sugar levels over 125 mg/dl or random blood sugar over 199 mg/dl. Type 2 diabetes is a leading cause of blindness, stroke, heart attack, amputation and kidney disease. By 2025, it is estimated that over 300 million adults worldwide will have diabetes, with India and China having the highest numbers of people affected. Early diagnosis and treatment can help prevent or delay complications. Managing diabetes involves following a healthy diet, regular exercise, taking medication as prescribed, and regularly testing blood sugar levels.