Diabetes is mostly a lifelong disease that cannot be cured, but some patients, especially those with type 2 diabetes, have hope that their diabetes can be reversed. In case of secondary diabetes, it may also be cured by eliminating the secondary factors. Diabetes is categorized into type 1 diabetes, type 2 diabetes, gestational diabetes, and other specific types of diabetes. Type 1 diabetes requires lifelong treatment with insulin injections to keep blood glucose within the normal range and to prevent diabetic complications. Patients with type 2 diabetes can control their blood glucose by taking hypoglycemic drugs, such as metformin and glibenclamide, or inject insulin for treatment if the drugs are less effective. If high blood glucose is caused by drugs such as long-term application of glucocorticoids, blood glucose may return to normal after stopping the drugs. If the high blood sugar is caused by Cushing’s syndrome, hyperthyroidism or other diseases, the blood sugar may return to normal after treating the primary disease. Patients with diabetes should follow the doctor’s instructions to use medication, and should not reduce or stop medication without authorization. Regular monitoring of blood glucose, diet and exercise are also necessary to keep blood glucose within a reasonable range and to avoid progression of the disease.