One of the many means used to reduce post-operative infections is the preventative, or "prophylactic", administration of antibiotics just before and just after surgery. Because antibiotics, and for that matter surgery itself, alter the body's natural immune and inflammatory responses and the makeup of the bacteria in the intestine, there is a great deal of scientific interest in using the supplementation of bacteria that naturally reside in the intestine. It is felt that by doing so, the alterations in the immune response may be corrected and the patient better able to fight infections. There are studies using probiotics that have demonstrated a reduction in infection rates in patients undergoing abdominal surgery.