Alcohol-induced hypoglycaemia is a well-known phenomenon in insulin-treated diabetic subjects. Less attention has been paid to the impact of alcohol on blood glucose and insulin responses in non-insulin dependent diabetic subjects. The aim of this study was to investigate the acute metabolic effects of different alcohol contents added to a non-alcohol beer in 10 non-insulin-dependent diabetes mellitus (NIDDM) subjects. The patients received 500 ml non-alcohol beer with an alcohol percentage (v/v) of 0 (A), 2.7 (B), and 5.4 (C), implying identical contents of ingredients except for alcohol. Blood glucose (mean +/- SE) responses were similar in the three situations (395 +/- 59, 365 +/- 86 and 261 +/- 26 mmol/l x 240 min). In contrast, the incremental insulin response areas increased dose dependently to alcohol (5430 +/- 1158, 9336 +/- 2172 and 12336 +/- 2922 pmol/l x 240 min) and showed a linear correlation (r = 0.39; P < 0.03). The average suppression of serum free fatty acid was similar in the three situations (72.4 +/- 4.4%, 76.3 +/- 6.0% and 68.2 +/- 6.3%). In conclusion, intake of small amounts of alcohol does not acutely deteriorate the glycaemic control in NIDDM. The fact that alcohol results in a dose-related elevation in insulin levels with unaltered blood glucose and free fatty acid responses in NIDDM points to an aggravation of insulin resistance.