The author points out the presence of destructive forces within every therapeutic group, that he defines anti-group. This is a broad term that not describes a static thing, that occurs in all groups in the same way, but a set of attitudes and impulses, conscious and unconscious, that manifest themselves differently in different groups. These destructive forces intend to deny any value to group therapy, often causing attacks on the group, distrust and sometimes the break down of the group and his end. To recognise and elaborate the destructiveness expressed in the anti-group leads the group’s members to transform this experience in an entity with intrapsychic significance, a non-idealized object which allows an authentic transformation. In the article some parallels with wider social themes are also proposed.