Abstract: A method and device for detecting extravasation employs a non-invasive sensor system deployed on the skin to identify changes in both subcutaneous interstitial fluid pressure and skin temperature. Preferably, the system monitors the sensor system outputs to identify a sequence of a skin temperature drop followed by a interstitial fluid pressure increase. This pattern is distinctive of the occurrence of extravasation, thereby providing very reliable detection. Most preferably, a simple sensor structure based upon multiple piezoelectric film sensors is used.