A clinical evaluation was carried out in 19 maturity-onset diabetics to assess the effectiveness of glipizide in the treatment of newly diagnosed patients (11) not responding to diet alone and of patients (8) who had been inadequately controlled on other oral antidiabetic agents. Patients were studied over a period of 6 months. All of the 11 newly diagnosed patients were adequately controlled with glipizide in a dose of 5 to 15 mg/day (mean 9.6 +/- 3.7 mg/day), as were 5 of the 8 previously treated patients with a dose of 10 to 25 mg/day (mean 18 +/- 6.7 mg/day). None of the patients became hypoglycaemic nor did the blood sugar levels indicate hypoglycaemia in the fasting state. Serum triglyceride levels did not change significantly during glipizide therapy, neither did the patients' weight. No side-effects were reported.