The term ‘off-label use’ is generally taken to mean the prescription of a drug without approved official authorization. The present article deals with ethical problems associated with the off-label use of antipsychotic drugs for the treatment of behavioral and psychological symptoms of dementia (BPSD) in Japan. Before the introduction of the Law of Protection of Private Information, the off-label use of antipsychotics was an almost open secret in Japan. Indeed, users of mental health care make strong requests that they receive the best and newest treatment available. Here, a huge gap exists between what psychiatrists consider ‘best’ and what the health service authority approves. For the sake of patients' interest, psychiatrists cannot help prescribing a drug for an unapproved indication or in a dose outside the usual range, otherwise they are unable to effect a therapeutic outcome. Although thioridazine and vegetamin are officially approved for the treatment of geriatric psychosis in Japan, they are not used commonly compared with atypical neuroleptics. Clinicians' preference for atypical agents over conventional neuroleptics is based on ethical motivation regarding the safe use of the drug rather than profitability. The failure to follow the information on the drug label should not necessarily preclude a psychiatrist from making a good clinical judgment in the interest of the patient. Even so, the psychiatrist should be aware that the patient retains the right to redress for possible medical malpractice. Japanese psychiatrists should take into account the evidence concerning the effectiveness of the drug for any unlicensed indication when they prescribe it off-label. They should also inform patients of the fact that the prescription is off-label and of any risks and benefits involved in the prescription of that particular drug. Whenever there is evidence of benefit, a trial of the drug should always be performed under careful clinical monitoring.