Scrum glucose, growth hormone and cortisol were determined at 1 a.m. and 7 a.m. in 40 patients with diabetes mel-litus. 18 cases were treated with cyproheptadine. Effect of cyproheptadine on 'dawn phenomenon' of diabetes mel-litus was observed. The results showed that serum glucose, growth hormone and cortisol were higher at 7 a.m than at 1 a.m. Cyproheptadine could significantly decrease 7 a.m. serum glucose, growth hormone and cortisol. Those data suggested that diabetic dawn phenomenon has concern with the increase of growth hormone and cortisol level and cyproh...