Milk-Alkali syndrome is a well-known disease which presents hypercalcemia, alkalosis, renal failure after ingesting large amount of calcium and alkali supplements. Its prevalence had been increasing because of its use for peptic ulcer disease since Sippy regimen had been introduced. In 1980's, it became rare disease after H2 blocker treatment was popular. But recently, its prevalence is increasing because of high incidence of osteoporosis. And frequent use of phosphorus binder in renal failure patients. Secondary hypoparathyroidism mainly developed after total thyroidectomy for thyroid cancer which shows increasing incidence in Korea, also may be the reason attributable to increasing Milk-Alkali syndrome. We present 2 cases of Milk-Alkali syndrome after recommended doses of calcium carbonate supplement in secondary hypothyroidism due to total thyroidectomy. Both cases were all women over 60 years, co-administering vitamin D supplement as risk factors. In high susceptible population for developing Milk-Alkali syndrome, we must pay attention to and be well aware of the disease. [Korean Journal of Bone Metabolism, 15(2): 163-168, 2008]
