Liquid nitrogen freezing corns to clarify the following precautions: 1, understand the principle of liquid nitrogen freezing, liquid nitrogen freezing is the use of low-temperature liquid, the liquefied state of nitrogen close to minus -196 ℃, after freezing will inevitably appear tissue necrosis, edema, crusting. The appearance of mild pain is normal, do not have to worry too much; 2, after liquid nitrogen freezing, the appearance of small blisters, blood blisters, if the slight swelling and pain unnecessary puncture, pay attention to protection, do not secondary infection, but the pain is obvious need to draw off the blisters, to pay attention to protection, can be properly coated with iodophor or mupirocin ointment external band-aid protection, to avoid secondary infection; 3, because of the cryogenic effect of liquid nitrogen freezing with. Although the rapid rewarming after leaving this environment, but encounter some patients with strong peripheral circulation, liquid nitrogen freezing after the effect is poor. So liquid nitrogen freezing should not be immediately after the local warmth, may reduce the effect of freezing.