This study will collect and analyze peritoneal fluid for the existence and characteristics of stem cells from 15 patients undergoing scheduled elective intra-abdominal surgery by designated surgeons at Cedars-Sinai Medical Center. The types of abdominal surgery could be open abdominal surgery or laparoscopic surgery. Peritoneal washing is routinely done in abdominal surgeries. We will collect these fluids to analyze whether stem cells exist in human peritoneal cavity. The fluids will be collected in a sterile fashion. The collected fluid will be further processed in the laboratory for the purpose of the study.