The concentration of propofol in patients' exhaled air, which may reflect plasma concentration noninvasively, is an indicator of depth of general anesthesia. Real‑time monitoring of exhaled propofol may be helpful to realize individual propofol anesthesia. A variety of methods have been published for real‑time monitoring of exhaled propofol. However, there is still no optimal method that is widely accepted for online monitoring exhaled propofol. In addition, many factors were verified to have impact on measuring results. This article will review the characteristics of these methods and the factors affecting the detection of exhaled propofol. Accurate measurement of exhaled propofol has important guiding significance for monitoring the depth of anesthesia. Studying the affecting factors and optimizing the determination methods will make monitoring exhaled propofol more suitable for clinical use.