Although insight, positive attitude towards therapy and compliance are key to a successful treatment, in certain situations the use of coercive measures on mentally ill or disordered minors is the only way to prevent serious harm to the patient or others. The decision to use coercive measures, such as involuntary admission or detention, seclusion, mechanical or chemical restraint or involuntary treatment, is challenging for clinicians as they have to deal, not only with the patient and his or her parents who are in a disturbed emotional state, but also with some complex legal regulations. To protect the rights of patient and parents in these difficult situations and to prevent legal consequences for clinical personnel for unlawful acts, it is essential that staff be familiar with all concerned legal rules and procedures. Interdisciplinary co-operation between the involved professionals should be encouraged to ensure a standardised procedure according to legal specifications. A growing number of mental hospitals for children and adolescents have no special locked door units but open wards that can be locked when required. A placement of voluntarily and involuntarily committed patients in the same unit can cause problems if the freedom of voluntary patients is restraint due to the placement of an interned patient. Unlawful restraint must be avoided by a sufficient number of staff and clear proceeding guidelines.