Bloodstream 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.

Patients will be randomized to receive either twice-daily intraoral grape-flavored xylitol-wipe (intervention arm) or grape-flavored saline wipe (control arm) application in addition to the current standard of care (SOC). The purpose of this study is to determine whether xylitol wipes are effective at reducing bloodstream infections (BSIs), dental plaque, mucositis (redness and ulcers in the mouth), or gingivitis in patients who undergo allogeneic stem cell transplant (SCT).

Inclusion Criteria:

• Provide signed and dated informed consent and assent (when applicable) form
• Willing to comply with all study procedures and be available for the duration of the study
• Admitted and planning to undergo an allogeneic stem cell transplant (SCT) at Cincinnati Children's Hospital Medical Center (CCHMC), Boston Children's Hospital, or Children's Hospital of Colorado (Denver).
• Male or female, 4 months to 25 years of age at the time of SCT (Day 0)
• Have a minimum of one tooth
• Agree to avoid chewing gum and toothpaste that contains xylitol during the intervention period

Exclusion Criteria:

• Prior radiation treatment for cancer of the oral cavity, head, or neck in the past 6 months per the study participant's medical record
• Cranial boost in patients receiving total body irradiation
• Known history of allergy to xylitol
• Known history of allergy to grapes or grape flavoring
• Undergoing a conditioning-free allogeneic stem cell transplant (patient does not receive any chemotherapy or radiation prior to stem cell infusion)

Participants, parents/guardians, nursing staff (interventionists), oral evaluators, and investigators will be blinded to the intervention, administered in the form of twice-daily grape-flavored xylitol wipes or grape-flavored saline wipes (controls). Preformed packets will be prepared by CCHMC Investigational Pharmacy staff, which will consist of either saline wipes with natural grape flavoring or xylitol. The color, taste, and smell of the wipes will be identical. The statistician will be unblinded to treatment assignment for the analysis.