There is still limited systematic research on the effectiveness of psychotropic drugs used in liaison psychiatry settings. All drugs available in clinical psychiatry for the treatment of psychiatric disorders can be used in liaison settings. However, before choosing a specific drug, liaison psychiatrists must address additional important issues beyond those related to the indication for a psychotropic drug. Most psychotropic drugs used today are aimed at g-protein coupled receptors such as serotonergic (5HT). The availability of psychotropic drugs varies to some extent between countries within the European Union. This chapter discusses the most frequently used drugs. Depressive disorders accompanying physical illness should be treated to improve quality of life and treatment adherence. The main indications in liaison psychiatry settings are behavioural disorders caused by organic brain dysfunction including temporal lobe epilepsy, acute mania, pain disorders and prophylactic treatment of bipolar disorders.