The aim of this study was to determine whether infants absorb aluminium from antacid therapy. The study was conducted at Torrens House, a service provided by Child and Adolescent Health Services (CAFHS) for feeding and settling problems. Over an 11 week period, all patients receiving antacid therapy were studied. Patients not receiving antacids but of similar age acted as controls. Plasma and urine levels of aluminium were measured. The 15 infants receiving antacids had higher aluminium levels than the 17 controls (plasma 3.3 +/- 2.2 mumol/L vs 1.5 +/- 1.5 mumol/L, P less than 0.01; urine 25.1 +/- 27.6 mumol/L vs 1.1 +/- 1.8 mumol/L, P less than 0.004). The response was variable with 50% of infants receiving antacids recording plasma aluminium levels previously associated with toxicity in patients with renal failure after chronic exposure to aluminium. We conclude that infants absorb aluminium from antacids and suggest that patients receiving have their plasma levels monitored to identify those at possible risk of toxicity.