Increased bicarbonate is often seen in metabolic alkalosis. Metabolic alkalosis is common in two clinical conditions, one is hypochloremic alkalosis caused by electrolyte disorders, and the other is compensatory changes in the body caused by chronic respiratory acidosis. The first case requires active electrolyte supplementation, and bicarbonate will naturally fall after correction of electrolyte disorders. If it is accompanied by a significant increase in pH, arginine supplementation therapy is required under close monitoring. In the second case, treatment is needed for the primary disease, such as acute exacerbation of chronic obstructive pulmonary disease combined with type 2 respiratory failure and respiratory acidosis, and active anti-infection, wheezing treatment and non-invasive respiratory therapy will be given. Two points should be noted: one is that bicarbonate decreases slowly compared to the improvement of respiratory acidosis, often taking several days; the other is that arginine supplementation is prohibited in respiratory acidosis with elevated bicarbonate.