AIMS--(1) To evaluate the performance of in-house and pre-poured commercially available enteric agar by challenge with a large number of positive clinical specimens. (2) To set the standard (critical independent evaluation) which new products should reach. (3) To publish this information, so that others can make informed decisions about enteric media. METHODS--Thirteen media of anonymous source were challenged with "known" positive stool samples. RESULTS--In-house desoxycholate citrate agar performed best for overall pathogen isolation rates, for shigella isolation rates, and for most pathogens available on primary culture. CONCLUSIONS--Desoxycholate citrate agar made by our own laboratory yielded the most pathogens and proved the most effective.