We used a cytotoxin neutralization assay, a latex agglutination test, and an automated enzyme immunoassay to test fresh stool specimens from 122 patients with diarrhea. Twenty-eight (23%) of the specimens were shown to be toxin positive on the cytotoxin neutralization assay. The automated enzyme immunoassay detected 20 of the 28 specimens, and the latex agglutination test detected 14. The automated enzyme immunoassay and latex agglutination tests give specific results compared with the cytotoxin neutralization assay. These two tests are less sensitive and more costly, however, and should be reserved for cases in which physicians require rapid results.