Severe neurologic complications resulting from correction of hyponatremia are common, but reports of nonneurologic sequelae are scarce. This article describes a patient in whom rhabdomyolysis developed during correction of severe hyponatremia attributable to psychogenic polydipsia. Relevant material about volume regulation in the cell is presented, and a potential mechanism of cell damage is proposed. This case report emphasizes the importance of monitoring for nonneurologic complications during correction of hyponatremia.