Is There Evidence of Toxicity in Long-Term Photobiomodulation?

This editorial briefly discusses the issue of potential toxicity in the case of long-term photobiomodulation (PBM). Scientific articles from PubMed, Google Scholar, and the China National Knowledge Infrastructure were included in a heterogeneous search. There have been very few studies on the long-term effects of PBM, as well as its potential toxicity. There is no evidence that PBM is toxic when used at therapeutic or imaging doses. There are no such concerns with intracranial PBM application (e.g., optical fiber) in either animal or human experiments.