Lactobacillus Plantarum in Preventing Acute Graft Versus Host Disease in Children Undergoing Donor Stem Cell Transplant

Inclusion Criteria: * All clinical and laboratory studies, if applicable, must be obtained within 21 days prior to start of protocol therapy (repeat if necessary); protocol therapy must begin within 6 months of study enrollment * Patient must have a diagnosis that is managed with an alternative donor allogeneic hematopoietic cell transplant * Patients must have a Lansky (for patients =\< 16 years of age) or Karnofsky (for patients \> 16 years of age) performance status score of \>= 70; patients who are unable to walk because of a chronic underlying condition (such as paralysis), but who are up in a wheelchair, will be considered ambulatory for the purpose of assessing performance score * Hematopoietic cell transplant (HCT) * Patient must be receiving cells from alternative donor defined as one of the following: * Unrelated donor with a complete human leukocyte antigen (HLA) match or a 1 or 2 HLA mismatch, considering only HLA-A, HLA-B, HLA-C, and HLA-DRB1 * Related donor with a 1 or more HLA mismatch (including haplo-identical) * Note: History of HCT or other cellular therapy (e.g. chimeric antigen receptor \[CAR\]-T cells, donor lymphocyte infusions) is permitted Exclusion Criteria: * Patient plans on receiving stem cells from a matched (8/8) related donor * Patient has used a probiotic dietary supplement within the previous 30 days of enrollment; (consumption of yogurt products is allowed) * Patient has a history of severe GI tract insult including but no…