The 'anti-group' is a concept which challenges the conventional optimism of group psychotherapy. The disruptive elements it comprises place a burden on the therapist and threaten the integrity of the group. Nevertheless, understanding the 'anti-group' offers therapists new perspectives on the nature of relationships and alternative strategies for managing destructive behaviour. Theories of group psychotherapy tend to polarise creative and destructive aspects. Morris Nitsun offers critical evaluations of the contributions made by S.H. Foulkes and Wilfred Bion, and demonstrates how, in practice, the forces interact and even complement each other. The 'anti-group' which manifests itself in a variety of ways ranging from demoralization to excessive dropping out, expresses the frustration and anger that patients often experience. These feelings are invoked in intense ways during group sessions. Recognising the 'anti-group' offers the therapist alternative coping strategies, helps liberate the creative processes and strengthens the theoretical base of group psychotherapy. Taking a wider view of the subject, Morris Nitsum places the 'anti-group' in the context of universal ambivalence about groups, which is evident in social settings such as the family, the workplace and the culture at large.