Corns cryotherapy can generally be used to oval forceps clamp cotton ball dipped in liquid nitrogen pressure freezing, the operation process includes the preparation of the refrigerant and freezing operation. Liquid nitrogen and carbon dioxide are commonly used as freezing agents, and liquid nitrogen is generally used for treatment. According to the size of the skin lesions into the corresponding size of the cotton ball, with oval forceps clamped cotton ball into the warm bottle containing liquid nitrogen cotton ball dipped in liquid nitrogen quickly removed and placed on the lesion, pressing hard for 30-40 seconds, because the cotton ball dipped in liquid nitrogen is not much, evaporation of the fast must be dipped several times. Thick skin lesions are frozen for a longer time, so that the treatment site becomes white, in order to achieve the therapeutic purpose. Loss of sensation and the elderly blood from the poor lower extremities. Long-term use of steroid therapy, radiation damage to the skin and chickenpox skin disease should be careful with freezing. In addition, severe peripheral vascular disease, coagulopathies, cold urticaria and other contraindications to cryotherapy. If there is any discomfort, it is recommended to consult a doctor promptly.