In a longitudinal study, antiasthmatic and metabolic effects of budesonide inhalations in initially high (800 micrograms/m2/day for 1 month) and subsequently lower (400 micrograms/m2/day for 4 months) dosage were evaluated in nine children with asthma, aged 5 to 10 years. The FEV1 increased significantly after high dosage (median, 96.5% versus 105.5%; p = 0.0339). After lower dosage, FEV1 was still higher than at the baseline (106% versus 96.5%; p = 0.0339). Clinically, no additional beta2-agonist was needed after 2 weeks of treatment. Serum high-density lipoprotein cholesterol increased significantly by 22% after high dosage (medians, 1.18 versus 1.44 mmol/L). A significant decline to 1.31 mmol/L was observed when the dose was reduced (overall, p = 0.0319). The treatment had no significant effect on serum total cholesterol, on serum triglycerides, on the ratio of high-density lipoprotein to total cholesterol, on the body mass index, or on glucose tolerance. The high dosage increased significantly the ratio of serum insulin to blood glucose, calculated from the areas under the incremental 2-hour curves in the glucose tolerance test (medians, 17.3 versus 23.2 mU/mmol). After lower dosage, the ratio declined significantly to 13.5 mU/mmol (overall, p = 0.0164). No significant changes were observed in plasma cortisol in the 2-hour adrenocorticotropic hormone test. The antiasthmatic effect of budesonide inhalations in a dose of 800 micrograms/m2/day for 1 month was accompanied by detectable changes in lipid and carbohydrate metabolism. These metabolic changes were reversible, and the antiasthmatic effect could be maintained by a dose of 400 micrograms/m2 for 4 months without significant systemic effects. This dose is safe and efficient in the maintenance treatment of childhood asthma.