The present invention relates to a physiological monitor and system, more particularly to an electroencephalogram (EEG) monitor and system, and a method of detecting the presence or occurrence of suppression in the EEG signal. Accurately detecting signal suppression in real-time provides the clinician with the ability to prevent possibly severe, long-term damage to patients as a result of excessive anesthetic or sedative. The present invention provides such a system and method for accurately and automatically detecting suppression in physiological, particularly EEG, signals in real-time and allowing for the administration of treatment or medication to reverse the effects of such situations, or minimize the harm caused. The present invention also allows for the use of closed-loop treatment or drug delivery systems to further automate the process and provide rapid treatment to a patient to reverse or minimize potential harm.