After short-term contraction and expansion of skin blood vessels after negative ions, it can improve microcirculation and tissue nutrition, accelerate epithelial regeneration, have antibacterial effect and promote wound healing. Animal experiments show that inhaling negative air ions can speed up wound healing by 20%. Negative ions can enhance the function of mononuclear phagocyte system, increase the antibody content in blood, improve the nonspecific immune function of the body and have desensitization effect. Some people inhaled negative air ions into allergic shock animals, and found that compared with the control group, it can alleviate the disease and shorten the course of disease. It has also been found that negative air ions can enhance the body's resistance to diphtheria toxin.