The side effects of drugs are deemed so important that their pubblication are strictly regulated by national health agency. But no one agency requires such warnings connected to other mental health treatment including Psychotherapy. in contrast to all pharmacotherapy studies in groups of patients, there is precious little information about the safety of psychotherapeutic interventions, which are also, in some patients and in some instances, associated with adverse events that need to be noted. Actually empirical research on the negative effects of psychotherapy is largely insufficient, partly there is a lack of theoretical concept on how to define, classify and assess psychotherapy adverse effects. This is a badly understudied issue, but of high clinical relevance, given that these treatments are so frequently recommended for the management of patients with psychopathological problems. and while there are many different forms of psychotherapy, virtually all of them share the matter discussed in this paper. Unfortunately, many psychotherapists won’t discuss or acknowledge about side effects, despite they occour all the time. Some plausible definitions are considered as “unwanted events”, “adverse treatment reactions”, “deterioration of illness”, “malpractice reactions”, “treatment emergent reactions”, “treatment non response”, “therapeutic risks”, “controindications”. Now that psychotherapy has become an accepted and effective treatment option within the health care community, researchers and therapists need to do a better job of describing and examining the negative side effects of psychotherapy. Recognition of adverse treatment effects have to be a characteristic of good therapists and treatments, to improve the quality of care.