The pyrogenic cytokine IL‐6 which is generated by infection stimulated macrophages and dendritic cells (DCs) is an important cytokine relevant with fever, both in the induction of temperature rise and the downstream mediation of lymphocyte trafficking to lymphoid organs and tumors.5 To investigate a fever‐like symptom by mild heat, we compared the level of IL‐6 among three groups: (1) normal mice treated with PCN without light, (2) normal mice treated with PCN‐based light stimulation, and (3) normal mice treated with lipopolysaccharides (LPS) as the positive group. The gene discussed is IL6; the disease is infection.