Consultative and liaison psychiatry is a sub-discipline within psychiatry and psychotherapy. It provides care for patients who are being treated in acute care hospitals, rehabilitation clinics or nursing homes, and who have mental or psychiatric disorders in addition to an underlying physical disease.

Strictly speaking, consultative psychiatry involves giving diagnostic and therapeutic advice to other non-psychiatric medical disciplines from a psychiatric and psychotherapeutic perspective.  Liaison psychiatry describes a psychiatrist's ongoing, integrated and institutionalised collaboration with other staff in a hospital or department that primarily treats patients suffering physical conditions. Liaison psychiatry facilities can be found, for example, in pain clinics, intensive care or transplant units, oncology wards or dialysis departments.

Consultative and liaison psychiatry takes into account and understands the complex interactions of psychological, social and biological factors that jointly determine the course of a disease and its treatment plan. The aim of consultative and liaison psychiatry is to detect and treat mentally ill patients in medical facilities as efficiently as possible. This includes the early detection, prevention, diagnosis and treatment of mental disorders and (if necessary) the referral of patients to psychiatric care services.