We have attempted to quantify the degree of inflammation associated with oral lesions through the use of infrared thermography, since the increased vascularity associated with inflamed tissue might result in measurable increases in surface temperature. This would provide a better measure of the relief of pain and inflammation associated with cancer chemotherapy mucositis by an antiinflammatory drug such as benzydamine hydrochloride than the subjective pain scales now employed. One subject with normal oral mucosa and three subjects with oral lesions of varying aetiology were studied with a Hughes Series 4000 PROBEYE thermal video system utilizing an infrared imager and microprocessor. A 35-mm camera was used to obtain a colour photograph of each subject. Multiple thermograms were made in a temperature range of 30.0 degrees C to 34.2 degrees C at a sensitivity of 0.2 degrees C. Photographs were taken on different occasions to determine whether the temperature readings could be duplicated and to test the accuracy of each reading. The normal surface temperature of the control subject's mucosa was found to be significantly cooler than clinical areas of inflammation in patients with lesions induced by chemotherapy. The temperature of the areas of stomatitis was remarkably consistent (Subject C means 33.7 degrees C; Subject D means 33.9 degrees C). Interestingly, the necrotic center of a traumatic ulcer inhibited measurement of an underlying inflamed base and was thus equivalent in temperature to the normal control (Normal means 31.9 degrees C; Subject B necrotic lesion means 31.7 degrees C). These results suggest that infrared thermography may represent a means to assess quantitatively the degree of mucosal inflammation. Additional studies are in progress.