Local anaesthesia for minor surgery can be produced by reducing the skin temperature, but slight reduction of the skin temperature, insufficient to cause local anaesthesia, is also said to relieve pain and muscular spasm. For many years ethyl chloride sprays have been used for this purpose. The way in which skin cooling without local anaesthesia acts is not known. It seems to be related to the intensity of afferent stimulation,1 but changes in vascular tone, counterirritation and perhaps partial anaesthesia may be involved. The treatment may also have a psychological effect.