An in vitro study using HN5 human HNC cell line found that metformin had a dose‐ and time‐dependent cytotoxic effect on cancer cells while sparing normal cells. The combination of metformin and laser irradiation significantly increased cytotoxicity (p < 0.05) and further downregulated the mTOR signaling pathway. This suggests a potential synergistic effect between metformin and laser therapy for HNC treatment. The gene discussed is MTOR; the disease is cancer.