Efficacy, safety, patient risks, and benefits must be evaluated when selecting a treatment. Photobiomodulation (PBM) is a drug-free, safe, and cost-effective treatment that shows optimal clinical outcomes for cancer treatment toxicities and oral diseases. Despite these benefits, adverse effects of PBM are underreported. No immediate adverse effects have been documented, but patients may experience numbness and increased pain at the application site, typically resolving within 24 h. No delayed adverse effects are reported, though concerns exist about stimulating residual malignant cells. Clinicians should inform patients of potential benefits and risks, follow biosafety measures, and conduct long-term follow-ups to ensure safety.