Experimental and some clinical evidence suggests that ingestion of cinnamon may improve metabolic measures in individuals with diabetes; however, few human studies have been designed to examine this association as their primary objective. In this study adult subjects 30 years of age or older with type 2 diabetes were randomized to treatment with 1,200 mg/day cinnamon or matched placebo. Blood pressure, hemoglobin A1c, fasting blood glucose, lipid profile, physical examination, and blood and urine chemistry were measured at baseline and at the 12-week follow-up end-of-treatment visit. In total, 59 subjects (40.7% female; mean age, 63.05±10.85 years) were recruited. Systolic blood pressure (SBP) declined from baseline values by 3.4±11.4 mm Hg in the cinnamon group and increased by 1.9±10.2 mm Hg in the placebo group (P=.06). In repeated-measures analysis, a significant by-treatment difference over time was detected (P=.02). However, when baseline SBP was included in the model as a covariate, change from baseline SBP was no longer associated with treatment. Although cinnamon added to the diets of spontaneously hypertensive rats has been shown to decrease SBP in a dose-dependent manner, results of the present study in humans suggest that the by-treatment difference in change-from-baseline SBP was a function of regression to the mean rather than a treatment-associated change.