The appropriate control of emotional responses evoked by environmental stimuli is an important innate mechanism for ensuring quality of life and even for survival. Inappropriate responses and decreased abilities to adjust to changed environmental situations can lead to psychiatric disorders, such as posttraumatic stress disorders, phobia and depression. Endocannabinoid signalling has emerged as one of the regulatory systems of the brain supporting appropriate emotional responses. As various components of the endocannabinoid system have become therapeutic targets, understanding the endocannabinoids' mechanism of action is an important research topic for a rationalized drug design and optimal therapeutic strategies.