The aim of the study was (1) to describe hormone responses in insulin-induced hypoglycaemia and (2) to investigate if a combined treatment with intravenous glucose and intramuscular glucagon (group A) would improve glucose recovery as compared to treatment with intravenous glucose alone (group B). Eighteen adult patients with insulin-treated diabetes mellitus admitted to the Accident and Emergency Department with hypoglycaemia (plasma glucose 1.23 +/- 0.15 mmol l(-1) on admission) were randomized to one of the above treatments and plasma glucose and counterregulatory hormones were measured before and 30-120 min after treatment. Pre-treatment counterregulatory hormone concentrations were significantly lower than hormone concentrations during induced hypoglycaemia in healthy control subjects but significantly higher than healthy fasting concentrations for plasma adrenaline (p = 0.020), glucagon (p = 0.008), growth hormone (p = 0.011), and cortisol (p<0.00001). Thus, although glucagon and adrenaline responses may be absent when studying Type 1 diabetic patients in the experimental setting, both hormones increase to a significant extent in 'real-life' hypoglycaemia in this patient group, although to a lesser degree than might be expected. Plasma glucose did not differ significantly between the two treatments at any time point. Despite access to food, one of four patients in group B and one of five patients in group A had plasma glucose below 4.0 mmol l(-1) after 120 min. In conclusion, low yet significantly elevated concentrations of adrenaline and glucagon were found in diabetic patients admitted with severe hypoglycaemia to an Accident and Emergency Department.