Methadone mixture DTF (1mg in 1ml) is a safe non-injectable alternative to methadone tablets (5mg). It also allows for a more gradual detoxification from opiate dependence. For these reasons it was decided to 'rationalise' our prescribing so that methadone in mixture form only would be dispensed. At the beginning of 1989, 66 opiate-dependent patients were receiving methadone tablets, 61 the methadone mixture. We report the consequences of instituting a policy change which was clearly very unpopular with patients. Of the 66 patients receiving methadone tablets prior to the change to mixture, 53 were represcribed tablets by the end of the 3-month follow-up period. In many cases this was because of an intense resistance to the change over, physical complications of methadone mixture occurred in very few. We were able to observe a decline in social stability and an increased use of non-prescribed drugs in some patients who changed to methadone mixture. More far-reaching consequences of the change included an increase in chemist break-ins, an increase in the street value of methadone tablets and greater hostility and threatening behaviour towards staff. These changes reflect psychological rather than pharmacological or pharmacokinetic effects.