Quaternary prevention avoids or mitigates the consequences of unnecessary or excessive activity of the health system. Iatrogenia produced by care systems activity is a serious public health problem and in mental health is poorly understood. The damage that can be inflicted to patients covers the entire episode of care, from prevention to treatment through the diagnostic process. We review the damage caused by preventive activities as the approach of mourning or debriefing, pharmacological and psychotherapeutic treatments, the iatrogenia produced in diagnosis and the deleterious effects of being under care in the psychiatric system especially related to stigma. Become aware of the seriousness of iatrogenic effects of our "well done" interventions allows foregrounding the importance of quaternary prevention and the need to work with the shared decision making model always considering alternatives and measures to ensure safety and rights of patients.