C. difficile has been reported as one of the most common causes of health careassociated infections in U.S. hospitals, thus it is important to know if the practice of providing these patients prophylactic CDI therapy is effective. CDI is expensive to treat and more importantly, it is associated with significant morbidity and mortality. Attributable mortality ranges between 5% and 10%. Furthermore, it was recently estimated that the inpatient cost of one episode of recurrent CDI was $11,631, with an overall cost to the health care system of $4.8 billion annually. Literature evaluating the role of secondary prophylaxis in high-risk patients is sparse. However, there are few recently published studies indicating that prophylaxis with oral vancomycin had an impact on the incidence of recurrent CDI. One of the studies was conducted at the University of Indiana Medical School. There were 203 patients with a history of CDI meeting criteria as high risk included in the study. The results demonstrated that one of 71 patients (1%) given oral prophylaxis experienced recurrence of C. difficile compared with 35 (37%) out of 132 patients not given the prophylaxis (p <0.001). Similarly, Wong and colleagues presented a study that included patients who were treated with antibiotics for a non-CDI indication 14 to 90 days following an initial CDI diagnosis. Patients receiving prophylaxis relapsed less often than the control group (6.25% vs. 19.3%; P = .003) — a 67.6% risk reduction.