Fourteen men aged 73-94 showed a fall in leucocyte ascorbic acid levels during five days' treatment with 1 g of tetracycline daily. A control group of nine men aged 74-90 showed no fall in leucocyte ascorbic acid levels. Of the control group, three were treated with phenobarbitone 60 mg thrice daily, three with phenylbutazone 200 mg thrice daily, and three with aloxiprin 1,200 mg four times a day. A further two men aged 87 and 90 showed increased urinary excretion of ascorbic acid while receiving 1 g of tetracycline daily.