Aluminium absorption from four doses of the antacid preparation 'Aludrox' when taken alone, with orange juice or with milk was compared by measuring the change in urinary aluminium following Aludrox dosage in 15 normal adults. There was an approximately 10-fold increase in 24 h urinary aluminium excretion following the Aludrox plus orange juice (232 micrograms) which was significantly higher than that following Aludrox alone (62 micrograms) (P < 0.001), but milk had no effect on aluminium absorption. The results showed that orange juice greatly enhanced aluminium absorption and should not therefore be taken in conjunction with aluminium-containing antacid preparations.