The advantages of long-term use of selegiline are better efficacy in controlling blood glucose and low risk of hypoglycemia; the disadvantages are that long-term use may cause headache, arthralgia, and elevated liver enzymes. 1. Advantages: Sitagliptin is used in the treatment of diabetes mellitus, which belongs to dipeptidyl peptidase inhibitors, through inhibiting the activity of dipeptidyl peptidase, reducing the inactivation of glucagon-like peptide-1, increasing the level of endogenous glucagon-like peptide-1, and promoting the secretion of insulin, so as to reduce blood glucose. Long-term use can keep blood glucose at normal level, and there is generally no risk of hypoglycemia. 2. Disadvantages: Long-term use of selegiline may cause headache, hypersensitivity reactions, elevated liver enzymes, upper respiratory tract infections, pancreatitis, arthralgia and other adverse reactions. Selegiline is contraindicated in pregnant women, children, patients with allergies and type 1 diabetes. Therefore, patients who need to use this drug should consult a doctor, take the drug under the guidance of a doctor, and seek medical attention if they experience any discomfort after taking the drug.