RecruitingPhase 2Clinical trialXylitol BSI Multisite - Reduction of Bloodstream Infections From Oral Organisms in Pediatric Stem Cell TransplantBloodstream infections (BSI) caused by bacteria translocating across injured oral mucosa are a significant cause of morbidity and mortality in patients undergoing stem cell transplantation (SCT). Unfortunately, there are currently no known strategies to prevent these BSI in this vulnerable population. The investigators will conduct a randomized, double-blind, placebo-controlled trial at three institutions to evaluate the effectiveness of twice daily intraoral xylitol-wipe application on reducing BSI in pediatric SCT patients.