Aluminium is the most abundant metal in the Earth's crust and humans are exposed to small amounts through food, water, cookware, antiperspirants, antacids, and occupational environments. At low levels the body excretes aluminium efficiently through the kidneys. At elevated levels — typically from dialysis, high-dose antacid use, or significant occupational exposure — aluminium can accumulate in the blood, bones, and brain, where it is toxic.

The kidneys are central to aluminium excretion, meaning people with chronic kidney disease (CKD) are at significantly higher risk of accumulation. Historically, aluminium toxicity was a serious complication in dialysis patients who were exposed to aluminium-contaminated dialysate. Modern dialysis uses purified water, but aluminium-containing phosphate binders are still occasionally used in CKD, making monitoring important.