The incidence of type 2 diabetes mellitus has risen globally, from 108 million cases in 1980 to 422 million cases in 2014. Although controlling glycemic levels in patients with diabetes is crucial, insulin and sulfonylureas can cause hypoglycemic episodes and even potentially fatal events such as comas, seizures, life-threatening arrhythmias, and myocardial infarctions. Several antibiotics have been documented to cause hypoglycemic episodes; the use of antibiotics along with insulin or sulfonylureas might further increase the risk of hypoglycemia. Therefore, researchers must determine which antibiotics carry a risk of inducing severe hypoglycemic events. The prevalence of H. pylori infection remains high in most countries, and the infection is often treated with triple therapy involving amoxicillin, clarithromycin, and a proton pump inhibitor (PPI). Several case reports have reported that hypoglycemia can occur when used with patients who also take diabetes medication. Therefore, we hypothesized that patients with diabetes have an increased risk of hypoglycemic episodes when being treated with triple therapy for H. pylori infection. By analyzing medical records from Taiwan’s National Health Insurance Research Database, we found a significant association between hypoglycemia and triple therapy treatment for diabetic patients with peptic ulcer disease. Prescribing triple therapy to patients with diabetes and peptic ulcers significantly increased the risk of a hypoglycemic episode (adjusted odds ratio [aOR] = 1.75, 95% confidence interval [CI]: 1.64 to 1.88, P < 0.001). Similarly, the highest aOR (5.77, 95% CI 4.82 to 6.92) was found in patients with diabetes and peptic ulcers who had hypoglycemic episodes within 30 days after triple therapy treatment. Many patients with diabetes require H.pylori eradication for peptic ulcer treatment, and vigilance toward the risk of hypoglycemia in this population is thus necessary.