Traditionally, behavioural psychotherapists have underplayed the significance of purely verbal means of effecting behaviour change. Verbal therapies have always been regarded with some suspicion and considerable doubts cast about their efficacy (Eysenck 1952; 1960). Even when writers have acknowledged that some change occurs from verbal interventions, their effects are generally seen as weak when compared to more active therapies (e.g. Bandura 1977). In reviews of evaluative research claims are made for the superiority of the behavioural approaches (Rachman 1971) and, even where no such claims are made, there is still the tendency to draw a distinction between behaviour therapy on the one hand, and the verbal or insight therapies on the other (e.g. Smith & Glass, 1977). It is my contention that this distinction is an artificial one; it ignores the fact that behavioural psychotherapists draw heavily on words in their treatments, and, indeed, that many verbal psychotherapists are often very active or behavioural in their work. In this paper I want to illustrate the power of words within behavioural psychotherapy by referring to what therapists actually do in practice. To make this explicit I shall describe a particular case in order to illustrate the way one behaviour therapist uses words for effect. More generally, I shall argue that verbal methods are already a highly significant feature of behavioural psychotherapy, that words, far from being weak in their effects, can be both powerful and efficient and that it is quite appropriate to use verbal methods of analysis and treatment without undermining the basic principles of a behavioural orientation.