It is said that diabetes is one of the factors contributing to the onset of dementia and accelerating its progression. The number of dementia cases is expected to increase steadily year by year. Such being the circumstances, we encountered an elderly woman with diabetes and dementia, who managed to lower her blood glucose values to a proper level somehow or other, thus lightening the burden of caregivers. We shall hereby report the case because we thought it would make a good example for care in the region where the population is rapidly graying. The woman, then at age 80, visited our hospital complaining of languidness. Her blood sugar level was so high (random blood glucose level: 1,096 mg/dl) that she was hospitalized at once. By a stepwise insulin reinforcement therapy, the blood glucose levels were under control. During the stay in hospital, she was also diagnosed as having senile dementia. She was provided with effective health care and education for the control of blood sugar levels. Having snacks between meals was strictly prohibited. Considering that she was an elderly person living alone, only internal medicines were given. As a result, her blood glucose levels were elevated to about 300 mg/dl, but the combined use of GLP-1 injection and internal medicine once a week had good control over blood glucose levels. So, the patient was discharged from the hospital.

　　A 63-year-old woman was admitted with complaints of thirst and polyuria about 1 year after ceasing therapy in November, X and in October, X+1. Her blood glucose levels at the beginning of her admissions were 347 at the first admission and 486 at the second admission. We administered glargine, a long-acting type insulin, 8U/day, and　a short-acting insulin, glulisine, 4U/day, during the first admission. We administered glargine, a long-acting type insulin, 4U/day, and a short-acting insulin, glulisine, 3U/day, during the second admission. We also administered a GLP-1 receptor agonist, liraglutide, 0.3mg/day. Blood glucose levels (mg/dl) during the 5 days of the first admission were as follows: first, -, -, 347, and 180; second, 273, 266, 109, and 188; third, 75, 192, 186, and 182; fourth, 93, 194, 91, and 144; fifth, 78, 95, 124, and 127. In the second admission, blood glucose levels were as follows: first, -, -, 486, and 299; second: 140, 137, 195, and 128; third: 101, 122, 114, and 108; fourth: 101, 123, 123, and 137; and fifth, 89, 136, 111, and 129. CGM data showed an average of 128mg/dl and standard deviation of 34 during the first admission. CGM data showed an average of 125mg/dl and standard deviation of 20 during the second admission. The reduction of insulin and rapid flattening of blood sugar were achieved by GLP-1 receptor agonist with promotion of insulin secretion and suppression of glucagon secretion.