OBJECTIVES--To ascertain changes in drug treatment of elderly patients after discharge from hospital and to identify areas of communication which may require improvement. DESIGN--Follow up of patients six to 14 days after discharge, when the drugs supplied by the hospital should have run out and a further supply obtained from the general practitioner. Patients were also asked about information supplied to them by health care professionals during their hospital stay. SUBJECTS--50 elderly patients discharged from five geriatric wards (mean age 76.9 years). SETTING--Sunderland District Health Authority. MAIN OUTCOME MEASURE--Drugs taken after discharge from hospital. RESULTS--After returning home the drug regimen of 45 patients differed from that prescribed on discharge from hospital, with 11 patients taking a different dose, 10 having stopped drugs, and 20 taking new drugs. Possible influencing factors included an incomplete drug history, the continuation of drugs taken before hospital admission, and changes in the prescription not attributable to a conscious clinical decision. Lack of information also contributed; 46 patients could not recall being told when to take drugs before discharge. CONCLUSION--Closer communication is needed between hospital and community health care professionals to ensure that patients are informed about their discharge prescription and continuation of treatment.