Cryosurgery offers a means of destroying tissue by subjecting it to extreme cold. The mechanisms by which cells die are as yet poorly understood, but reliable and predictable clinical results have been obtained in the treatment of a wide range of benign and premalignant oral lesions. Its effectiveness in the primary treatment of malignant oral lesion has not been adequately assessed but at least it offers palliation and relief of intractable pain where conventional cancer therapy has failed. The use of carbon dioxide 'snow' has been tested and found to be a simple and effective means of treating superficial benign lesions of the mouth.