The efficacy of diazepam suppositories as sedatives was investigated in anxious patients with defined advanced malignant disease. Twenty-four patients, age range 54 to 89 years (mean 72 years) with a mean weight of 52 kg, were randomly allocated 5 mg or 10 mg diazepam suppositories for 5 nights each in a crossover fashion, with a 2-day drug-free washout period in between. Sleep was rated daily as 'well', 'same' or 'badly' by the night nurse and by the patient. The majority of patients slept well while taking diazepam, with no apparent difference between the two doses. The most common side-effects reported were day-time drowsiness (58% of patients), dry mouth (29%) and amnesia (21%). No adverse reaction necessitated premature withdrawal from the study. Results indicated that diazepam suppositories were well tolerated and appeared to provide effective night-time sedation in anxious patients with terminal cancer.