The use of cold therapy in acute sports injuries as well as in the rehabilitation of the injured athlete has become a generally accepted treatment method. Various cooling modalities are used to apply cold to the injured area, e.g. ice packs, ice towels, ice massage, frozen gel packs, ethyl chloride and other vapocoolants, chemical reaction devices and inflatable splints using refrigerant gas. Most clinical studies report that the use of cryotherapy has a positive effect on pain reduction and on the recovery of various injuries. When the physiological processes produced by cryotherapy are examined in experimental situations, some of these reactions differ from expectations. Skin, subcutaneous, intramuscular and joint temperature changes depend on application method, initial temperature and application time. Intramuscular temperature continues to drop after the cooling modality has been removed. Results of various studies are consistent on the effects on neuromuscular and pain processes. Results of studies on cold and blood flow vary considerably, however it appears that blood flow increases with superficial cold application and decreases when cold is applied to large skin surface areas. Motor performance is affected by temperature with a critical temperature being around 18 degrees C, above and beneath which muscle performance decreases. There is also a critical temperature for the application of cold with inflammation and oedema increasing at temperatures below 15 degrees C. Precautions should be taken because prolonged application at very low temperatures could have deleterious effects.