Four cases of asthma (one adult, three children) developing acute adrenal crisis after introduction of high-dose inhaled fluticasone proprionate are presented. The three children, aged 7-9 yrs, had been prescribed inhaled fluticasone, dosage 500-2,000 microg x day(-1) and duration 5 months-5 yrs. All presented with convulsions due to hypoglycaemia (blood glucose 1.3-1.8 mM). The fourth case was a male of 33 yrs with difficult-to-control asthma and had been taking fluticasone propionate 1,000-2,000 microg x day(-1) for 3 yrs. He presented with fatigue, lethargy, nausea and postural hypotension. Acute adrenal crisis in each case was confirmed by investigations which included measurement of acute phase cortisol levels, short and long Synacthen stimulation tests and glucagon stimulation tests. Other cases of hypthoalamic-pituitary-adrenal axis suppression were excluded.