Gut bacteria have been incriminated as causing or contributing to generalized sepsis with multiple organ failure in severely ill patients, and selective decontamination of the gastrointestinal tract of Enterobacteriaceae has been claimed to decrease septic complications in these patients. We studied the effects of selective decontamination of the gastrointestinal tract on survival and organ function in an experimental model of sepsis with multiple organ failure. Wistar rats were inoculated intraperitoneally with zymosan and randomized into control or treatment groups (trimethoprim or streptomycin sulfate). Selective decontamination effectively prevented bacterial translocation of Enterobacteriaceae. However, only early mortality was decreased, and only so in the streptomycin-treated rats. Selective decontamination did not result in a significantly better condition of the surviving animals on day 12.