An overview of the literature and theories concerning revenge is presented in this study. The aim is to clarify the boundaries between a healthy and pathological way of dealing with revenge to improve diagnostics, with regard to both theory and clinical practice. Revenge is an intrapersonal phenomenon and the extent to which people need revenge has a certain degree of stability. A healthy way of dealing with revenge may restore the psychological balance that has previously been disturbed. However, the desire for revenge can be long-lasting and dysfunctional due to, among other things, early problems in development and specific personality traits. Consequently, a pathological way of dealing with revenge can be part of a disorder and can lead to destructive acts such as homicide and even mass murder. Some clinical examples are presented and points of attention regarding diagnostics and treatment are discussed.