The invention relates to an injection device for injecting dosed amounts of a liquid therapeutic agent, comprising a receiving system for the therapeutic agent, an application system for transferring the therapeutic agent to an application site, a dosing system for transferring the therapeutic agent from the receiving system to the application system, a trigger system for activating the dosing system, and a detection system 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.
