We investigated the emergency outpatients with diabetes due to drug-related severe hypoglycemia (requiring external assistance for recovery) who visited our hospital over a 10-year period (between April 2009 and March 2019) and found 329 cases (0.66 % of emergency outpatients). Elderly and lean patients accounted for the largest group. Patients with type 1 diabetes accounted for at least 11.2 % of patients. The mode of treatment was insulin in 42.2 %, combined usage of insulin and an oral hypoglycemic agent (OHA) in 16.4 %, and an OHA in 41.3 %. Most (86 %) patients treated with an OHA were administered sulfonylureas (SU). Among the patients treated with SU, 25.9 % had a reduced renal function, and 29.9 % were co-treated with a dipeptidyl-peptidase-4 inhibitor. Both the annual number of patients and their annual ratio to emergency outpatients peaked in 2009 and then decreased gradually. These decreases were largely due to a decrease in patients treated with SU.