Lithium is becoming an extremely popular agent in the treatment of many psychiatric disorders. Because of its low therapeutic index and dose- and nondose-related side effects, patients receiving this medication can have problems that may complicate their anesthetic course. We present two case reports showing some of the potential difficulties that may be encountered with the use of lithium and review pertinent pharmacology to enable the oral and maxillofacial surgeon to deal effectively with patients receiving lithium therapy who are about to undergo anesthesia and surgery.