Of 511 patients in two psychiatric hospitals, one-fifth had no psychotropic drugs, but over one-third (nearly half of those receiving medication) had a combination of two or more psychotropic drugs. Hypnotics and minor tranquillizers were commonly prescribed together with neuroleptics and anti-depressants. One-fifth of day-patients treated with depot neuroleptics also has oral neuroleptics. Anti-parkinsonian drugs were prescribed for half of those receiving neuroleptics. Both minor tranquillizers and neuroleptics were commonly administered three or more times a day. Forty per cent of patients treated with neuroleptics had diagnoses other than schizophrenia, and one-third of those receiving antidepressants had diagnoses other than affective disorder. An analysis of prescribing could contribute to a more rational use of psychotropic drugs.