A new selective medium, Butzler's medium Virion, for the isolation of Campylobacter jejuni from human faeces is described. This medium contains the following antibiotics per liter: cefoperazone 15 mg, rifampicin 10 mg, colistin 10,000 IU, and amphotericin B 2 mg. At 42 degrees C there was no difference in the isolation rate on Butzler's medium Virion and Butzler's medium Oxoid, but the competing faecal flora was best suppressed by the new medium which allows easier reading of plates and better recognition of campylobacter colonies. Also, the isolation rate and growth of faecal flora were comparable when this new selective medium was incubated at both 37 degrees C and 42 degrees C in a candle jar or a special incubator. These results suggest that Butzler's medium Virion is a very reliable medium for the isolation of campylobacter. In comparison with other selective media it has important advantages for investigators who have little experience in isolating this enteropathogen, or for developing countries where special 42 degrees C incubators are often not available.