Lithiumogenic disorders of the thyroid and parathyroid glands as surgical disease. Little notice has been paid in the surgical literature to problems with psychoeffective lithium, which by interfering with adenylate cyclase affects thyroid and parathyroid function, causing hypercalcemia, hyperparathyroidism, and hypothyroidism. Seven patients with lithiumogenic hyperparathyroidism occurring after years of lithium therapy underwent treatment and manifested osteoporosis (n = 2), hypertension (n = 2), nephrolithiasis (n = 1), coma (n = 1), rising hypercalcemia (n = 1), goitrous myxedema (n = 4), nephrogenic diabetes insipidus (n = 2), renal failure (n = 2), and hyperlipidemia (n = 1). Disease-directed parathyroidectomy (without morbidity) was curative. Unique laboratory findings included normal serum phosphorus and reduced urinary calcium and cyclic adenosine monophosphate values. Three separate cases of thyroid carcinoma after long-term lithium therapy were also treated, being preceded by myxedema (n = 2) and concurrent with hyperparathyroidism (n = 1). There has been only one previous report of lithium-associated thyroid carcinoma. All patients taking lithium should undergo surveillance for thyroid and parathyroid dysfunction and neoplasia, and appropriate surgical and medical treatment should be considered in each situation. Although hyperparathyroidism may be reversible with lithium discontinuance, such therapy may be obligatory for patient well-being, thus dictating parathyroidectomy. 