Viral hepatitis is easy to be combined with diabetes mellitus. Patients with hepatitis need nutrition, while diabetes mellitus requires controlled diet, and most oral hypoglycemic drugs have liver damaging effects. Therefore, the treatment of hepatitis combined with diabetes mellitus has its own specificity in clinical practice. The pathogenesis of hepatitis combined with diabetes may be as follows: 1. The decrease of insulin receptors on the membrane of target cells in peripheral tissues during hepatitis, and the decrease of affinity, which makes them less sensitive to insulin; 2. The virus or autoimmune damage to pancreatic islets, and the decrease of insulin secretion, which leads to diabetes; 3. In liver disease, the activity of most enzymes involved in glycolysis and the tricarboxylic acid cycle is reduced, resulting in a decrease in hepatic glycogen synthesis, a decrease in the ability of the liver and surrounding tissues to take up oxidized sugar, and a decrease in the function of regulating glucose metabolism. Since this type of diabetes is secondary to chronic hepatitis, in principle, liver disease should be treated first, active liver lesions should be controlled, liver function should be improved, and stability of diabetes should be promoted. The treatment should avoid entering too many carbohydrates, because glucocorticoids, thiazide diuretics, and insulin can aggravate the disorder of glucose metabolism or mask the symptoms of hypoglycemia, and should be avoided. For patients with stable hepatitis and mild diabetes, a controlled diet with small and frequent meals, appropriate protein increase, more fresh vegetables and vitamin supplementation should be the main focus. For patients with cirrhosis and chronic heavy hepatitis due to the large area of hepatocyte damage and poor compensatory capacity of liver function, insulin therapy should be preferred to control blood sugar. Oral hypoglycemic drugs, including sulfonylureas and biguanides, can cause liver function damage and should not be used.