This study investigated the establishment of a data base for use when assessing body temperature iin patients receiving aerosol therapy by face mask. Thirty subjects participated in two different treatment situations. Baseline temperature recordings were taken while subjects had heated aerosol administered through a standard face mask. Temperature recordings were repeated at oneminute and five-minute intervals after the mask was removed. Temperature recordings were repeated using cool aerosol treatments.An electronic thermometer was used for sublingual temperature recordings, and a polygraph with preamplifier and thermocouple interface was used to record changes in air temperature at the portal entry of the face mask. Constant monitoring of controlled ranges of aerosol temperature at the portal entry site allowed comparison of data during treatment. Significant effects were reported for both the cool and heated aerosol treatments. A comparison of mean baseline temperature with temperatures obtained at the measurement intervals yielded no change greater than three-tenths degree centigrade. This investigation suggested that a statistically significant change in oral temperature with treatments took place but there is relatively litle clinically significant change in oral temperature due to aerosol temperature's influence.