A multifunctional portable electronic device (100) that easily allows a user to test their breath-alcohol level is described. A power module (10) supplies a working voltage to an alcohol-testing module (12) and an output voltage generated according to a test result from the alcohol-testing module. A signal processor converts the output voltage of the alcohol-testing module into a digital signal and calculates out a corresponding alcohol concentration value that can be displayed on a display module (18).