Inhaled human insulin (Exubera((R)) [insulin human (rDNA origin)] Inhalation Powder) has recently been approved in the EU and the US for preprandial use in adult patients with diabetes mellitus. This formulation of insulin has a more rapid onset, but similar duration, of glucose-lowering activity compared with subcutaneously administered regular human insulin.Preprandial inhaled human insulin provided glycemic control that was comparable to preprandial subcutaneous regular insulin when added to long- or intermediate-acting subcutaneous basal insulin in patients with type 1 diabetes. Inhaled human insulin is also effective when administered alone, when combined with oral antihyperglycemic therapy, or when combined with basal subcutaneous insulin in patients with type 2 diabetes. Comparable rates of hypoglycemia occurred in patients treated with inhaled human insulin and in those treated with subcutaneous regular human insulin. Patients treated with inhaled human insulin demonstrated a greater decline in pulmonary function (forced expiratory volume in 1 second, carbon monoxide diffusing capacity) than patients treated with comparator antihyperglycemic agents; the mean difference between the treatment groups that favored the comparators was noted within the first several weeks of treatment, and did not change over a 2-year treatment period. This agent has also been associated with significant improvements in some quality-of-life and treatment satisfaction scores, especially when compared with subcutaneous mealtime insulin regimens.