The impact of alcohol on the severity of injury was studied by using injured patients from an emergency room in Helsinki, Finland. Blood alcohol content was estimated either clinically or with a breath test and then was recorded using a three-grade intoxication code (Ethyl sign). The study population was comprised of 14,995 men aged 15-64 years. The Ethyl sign was positive in 19.7 per cent. Hospitalization was used as an indicator of the severity of injury. Hospitalization was almost as common among sober (9.3 per cent) as among intoxicated patients (9.6 per cent) and the odds of being hospitalized, if considered 1.0 among the sober, was 1.03 among the intoxicated. However, the severity of injury correlated positively with the alcohol intoxication in the injured car occupants with an odds ratio (OR) of 3.1 (95 per cent confidence interval (CI) 1.7-5.6) and in those injured in falls from stairs (OR = 2.6; 95 per cent CI 1.4-4.7), but negatively in those injured in unspecified falls on the same level (OR = 0.3; 95 per cent CI 0.2-0.6). The effect of alcohol on injury severity seems to vary with the cause of injury.