Aluminum-related osteodystrophy, a crippling disease in patients with renal failure, can develop from the long-term ingestion of aluminum hydroxide gels. We present a diabetic patient treated with continuous ambulatory peritoneal dialysis (CAPD) who developed markedly elevated plasma aluminum levels but no musculoskeletal symptoms. Bone biopsy revealed features of the aplastic form of aluminum-related disease with significant aluminum staining, decreased osteoblastic osteoid, and decreased bone formation by double tetracycline labeling, but no excess accumulation of unmineralized osteoid. Aluminum hydroxide gels were discontinued and the patient received calcium carbonate to control hyperphosphatemia; 9 months later, a bone biopsy showed marked improvement of the aluminum-related bone disease, and at 2 to 10 months, plasma aluminum had decreased from 208.7 +/- 10.3 (SE) to 55.7 +/- 3.9 micrograms/L.