Baseline characteristics of studies included in the meta-analysis*.

Abbreviations: Allo - allogeneic hematopoietic stem cell transplant; Auto-autologous hematopoietic stem cell transplant; Chemo – chemotherapy; EORTC-European Organization for Research and Treatment of Cancer; GaAIAs/AsGaAI – gallium-aluminium-arsenide/arsenate; He-Ne- helium-neon; HSCT – hematopoietic stem cell transplantation; InGaAIP – indium-gallium-aluminium phosphide; LED – light emitting diode; NA – not available; NCI CTC – National Cancer Institute Common Terminology Criteria; OMAS – Oral Mucositis Assessment Scale; OMI - Oral Mucositis Index; Pub – published; Radio- radiotherapy; RTOG – Radiation Therapy Oncology Group; VAS – visual analog scale; WHO – World Health Organization.*There were 18 studies reporting 19 separate comparisons between low level light therapy and placebo/no therapy as one study stratified the population by underlying disease diagnosis and HSCT regimen.Baseline characteristics of studies included in the meta-analysis*.