Psychotropic drug prescribing in 1280 medical inpatients between 1973-75 was compared with that in 1200 similar patients during 1982-83. Three benzodiazepines accounted for 64% of prescriptions in 1973-75 and nine benzodiazepines for 82% of prescriptions in 1982-83. Over the decade, use of psychotropic drugs fell from 56% to 38% (P less than 0.001), primarily due to a reduction in patients treated only in hospital (34% vs 16%, P less than 0.001). Before admission, the proportions of patients receiving these drugs were similar (17% vs 18%). During admission, concomitant administration of similar drugs declined from 22% of patients in 1973-75 to 11% in 1982-83 (P less than 0.001), while concurrent prescribing before admission increased from 13 to 19%. The marked fall in psychotropic drug use and in inappropriate concomitant therapy indicates an encouraging trend towards more rational drug use at least in hospital. This was achieved without fiscal control and further rationalization of prescribing habits may be achieved by self-audit within the profession without legislative action.