This new method of frontal thermometry is based on a recording of the spontaneous reheating curve of the skin after cooling it to 25 °C. In cases of carotid stenosis, a thermal asymmetry of one of the three following kinds can be observed: thermal asymmetry from the start; asymmetry only during the reheating, or asymmetry during reheating and remaining afterwards. The reduction of the blood flow and a vaso-motor factor explain this asymmetry. This method allows better detection of clinical latent carotid stenosis.