A 51-year-old manic woman who developed acute severe lithium intoxication with neurotoxicity and nephrotoxicity during rapid abatement of manic episode was reported. The underlying causes of the serious toxicity were reviewed. Awareness and early detection of the toxic symptoms are emphasized in order to avoid permanent toxic sequelae. It is suggested that hemodialysis is the treatment of choice and should not be delayed, especially in severe toxic states and a daily 10 hours hemodialysis is needed to prevent the rebound effect as lithium in intracellular fluid equilibrates with extracellular fluid.