This study reviewed articles on lithium’s utility in the treatment of mood disorders. The safety, tolerability, teratogenicity, optimal dosing regimens, & mortality-lowering effects of lithium were reviewed. Lithium is the paradigmatic treatment for bipolar disorder. Optimal maintenance plasma levels may be approximately 0.75-0.85 mEq/L. Lithium-induced cardiovascular teratology appears to be less common than previously thought. Optimal lithium dosing may be once daily, this agent appears to bestow a robust suicide-lowering effect, & emerging data hint at neurotrophic & neuroprotective effects. (59 refs.)