We have shown that while transient functional bowel disorder occurred in 34.7% of patients (eight of 23 patients) recently infected with C difficile, only 4.3% of patients (one of 23 patients) had symptoms indicative of IBS after three months (ie, postinfectious IBS). Because an age-related reduction in immune responsiveness has been documented, it can be speculated that the low incidence of postinfectious IBS may be explained by the older age of the study population. Therefore, it cannot be excluded that the findings may be different in younger patients.