Acute ethanol (EtOH) intoxication is commonly associated with many medical and surgical problems which primarily or secondarily involve infection. Chronic EtOH ingestion has been associated with immune dysfunction and an increased risk of infection; however, the relationship of acute EtOH exposure and immune function has not been clearly defined. To determine if there is a relationship between acute EtOH intoxication and immune function, the effects of a single EtOH ingestion on immune function were studied in a rat model. Acute intoxication was produced by gavage feeding of 3 g/kg of EtOH, and immune function was evaluated by in vivo chemotaxis to a chemotactic peptide, N-formyl-methionyl-leucyl-phenylalanine and responsiveness of splenic lymphocytes to B- and T-cell mitogens. Chemotaxis was significantly suppressed at 4 hr (49.0 +/- 5.1% of control) after EtOH ingestion (P = 0.001), but returned to normal by 24 hr and remained at that level. However, acute EtOH ingestion showed no suppressive effects on lymphocyte responsiveness to either concanavalin A or LPS. These results indicate that a single ingestion of EtOH has the potential to transiently suppress chemotactic function of granulocytes but not affect lymphocyte mitogenic responsiveness in rats. This potential may contribute to increased susceptibility to infection in patients after EtOH ingestion.