Using a lactoferrin latex agglutination assay, we have compared the inflammatory responses to a cholera vaccine candidate, CVD 110, in which all known toxin genes have been deleted or mutated yet still produced significant diarrhea, with a less reactive vaccine strain and wild-type El Tor and O139 Vibrio cholerae strains. Data suggest that diarrhea due to attenuated and wild-type El Tor V. cholerae, and to a lesser extent O139 V. cholerae, involves an inflammatory response. Further study is required to further elucidate the mechanism of the process(es) involved.