Summary of outcomes of low level laser therapy as compared to placebo/no treatment.

Abbreviations: RR - risk ratio; SMD - standardized mean difference; WMD – weighted mean difference; CI – confidence interval;*Maximum anticipated mucositis was week 6±1 in head and neck cancer radiotherapy/chemo-radiotherapy trials and day 10±4 in chemotherapy and hematopoietic stem cell transplantation trials (from date of chemotherapy initiation and stem cell infusion respectively).** Severe pain defined as a visual analogue scale score >7.¥All analyses used a random-effect model. A risk ratio Summary of outcomes of low level laser therapy as compared to placebo/no treatment.