The aim of this study is to evaluate the effect and safety of chromium-containing milk powder in patients with type 2 diabetes mellitus. A randomized, double-blind, placebo-controlled trial was conducted in Taiwan. A total of 60 patients with type 2 diabetes mellitus, aged 30 to 75 years, and on a dose of gliclazide sulfonylurea agent (< or =160 mg/d) for at least 3 months were enrolled. Their glycosylated hemoglobin ranged from 7.5% to 12%, fasting plasma glucose (FPG) from 140 to 250 mg/dL, and body mass index from 20 to 35 kg/m(2). The subjects were divided into 2 groups, one group to receive chromium-containing milk powder (chromium 200 microg/20 g milk powder) and the other to receive placebo twice a day for 16 weeks. Frequently sampled intravenous glucose tolerance test (IVGTT) was performed before and after treatment. The chromium group demonstrated a lower FPG and fasting insulin (-38.1 +/- 9.2 vs 63 +/- 8. 5 mg/dL and -1.7 +/- 0.2 vs 1.9 +/- 0.3 microU/mL, respectively; P < .05), especially in male patients (-41 +/- 9.2 vs 85 +/- 11.7 mg/dL and -2.7 +/- 0.2 vs 3.1 +/- 0.3 microU/mL, respectively; P < .01), at the end of the study. Lower glycosylated hemoglobin was observed in chromium-treated male patients (-1.1 +/- 0. 5 vs 0.7 +/- 0. 2; P < .05). However, there were no significant changes in other metabolic parameters (lipid profiles including total cholesterol, triglyceride, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol), except improvement of insulin resistance (homeostasis model assessment for insulin resistance and insulin sensitivity index from frequently sampled intravenous glucose tolerance test) observed in male patients (-2.1 +/- 1.1 vs -0.41 +/- 1.12 and 0.18 +/- 0.11 vs -0.15 +/- 0. 2, respectively; P < .05). There were no adverse events in both groups, except for mild complaints in the chromium group on constipation (5%) and flatulence (5%). Intake of milk powder containing 400 microg/d of chromium for 16 weeks in subjects with type 2 diabetes mellitus resulted in lowering of FPG, fasting insulin, and improvement of metabolic control in male patients.