Milk-alkali syndrome is characterized by progressive hypercalcemia, systemic alkalosis, and renal insufficiency. After calcium carbonate is ingested with diary products, hypercalcemia and alkalosis may develop in susceptible persons, particularly those with underlying renal insufficiency. We describe a young woman who neither drank milk nor had peptic ulcer disease, yet who ingested enough calcium carbonate to require admission to an intensive care unit for acute renal failure. Chronically bulimic, she was taking Rolaids (Warner-Lambert Co, Morris Plains, NJ), which contained calcium carbonate, and was eating yogurt daily to prevent osteoporosis. We discuss the characteristics and complex metabolic interactions of the milk-alkali syndrome, a critical but generally reversible electrolyte disorder. Early recognition of coincident hypercalcemia and alkalosis and prompt cessation of calcium carbonate ingestion are essential for successful recovery. Finally, we suggest that nephrologists should discourage patients with renal insufficiency and chronic vomiting from consuming calcium-containing antacids and excessive dietary calcium.