We report a case of a 63-year-old male who has been admitted to the Emergency department with nonspecific symptoms. Lithium toxicity was not at first recognized. When we obtained sufficient information about previous medication and medical history, we measured lithium levels found to be 1.46 mmol/L. Although the value of lithium was mildly elevated, nephrotoxicity was produced leading to severe renal insufficiency and neurological symptoms. Hemodialysis was started, and we succeed to treat the patient without squeals. This case illustrates some of the factors that lead to lithium toxicity as well as the need to consider lithium toxicity to the differential diagnosis of a patient presenting with renal insufficiency with or without change in mental status and neurologic symptom.