The invention relates to an injection device (10) for injecting dosed amounts of a liquid therapeutic agent, comprising a receiving system (14) for the therapeutic agent, an application system (16) for transferring the therapeutic agent to an application site, a dosing system (22) for transferring the therapeutic agent from the receiving system (14) to the application system (16), a trigger system (28) for activating the dosing system (22), and a detection system (36) for detecting the amount of the therapeutic agent applied. According to the invention, a sensor arrangement comprises at least one recognition system which detects, prior to injection, whether the therapeutic agent has been mixed.
