Lithium is an indispensable pharmaceutical component of modern psychiatric therapy.The optimal steady-state concentration of lithium for maintenance treatment of bipolar disorders in generally considered to be 0.6 to 1.2 mmol/L.Because toxicity can occur at levels > 1.4 mmol/L,lithium must be carefully monitored and lithium dosage adjusted as necessary.In this case lithium intoxication occurred at a much lower blood concentration,at the lower end of the therapeutic range.This highlights the need for clinicians to closely monitor the clinical status of patients for early symptoms of intoxication,even when lithium levels are in the normal therapeutic range.