One hundred and fifty severely injured patients requiring long-term artificial ventilation were evaluated in a prospective, randomized, double blind study comparing the prophylactic effect of an intravenous immunoglobulin (Sandoglobulin; IGIV) against nosocomial infections with a placebo preparation. The groups were comparable in age, sex, injury pattern, and severity of the trauma. Seventy-six patients received 12 g of Sandoglobulin as a 3% solution on day 0, day 5 and day 12, i.e. a total of 36 g. Sandoglobulin significantly reduced the incidence of pneumonia (28 cases in the IGIV group, 43 cases in the placebo group, p = 0.0111). This resulted in a reduced therapeutic use of antibiotics. For the occurrence of sepsis (IGIV: 14 cases; placebo 19 cases) and other infections (IGIV: 11 cases; placebo: 10 cases) no significant differences were found. No side effects of the administration of IGIV were observed. IGIV prophylaxis neither reduced the overall death rate nor those deaths caused by infection. On day 5 after administration of the first 12 g of IGIV, the IgG serum concentrations were significantly higher in the Sandoglobulin group (8.41 +/- 1.96 mg/ml and 7.42 +/- 2.25 mg/ml respectively, p less than 0.001) whereas later serum samples showed no significant differences.