To summarize the quality of evidence for the efficacy of different biological treatments in mania, mixed state, and rapid cycling and to propose guidelines for treatment of these conditions. Articles published on treatment of acute mania, mixed states, and rapid cycling were reviewed and rated for quality of evidence using Periodic Health Examination guidelines. Lithium and divalproex sodium are effective in classical pure mania, whereas divalproex sodium and carbamazepine are likely more effective in mixed states. Divalproex sodium is likely more efficacious than carbamazepine and lithium when the mania is part of a rapid-cycling course. Typical neuroleptics are efficacious in acute mania, particularly in the presence of marked psychotic symptoms. Atypical neuroleptics can be useful in refractory mania. Some benzodiazepines do have antimanic effects, but they are increasingly being shown to have usefulness as adjuncts to mood stabilizers or neuroleptics rather than as primary antimanic agents. Electroconvulsive therapy (ECT) is an efficacious and broad-spectrum treatment. Mania can present with or without mood-congruent or mood-incongruent psychotic features and as part of a rapid-cycling or nonrapid-cycling course. Mixed state is a common presentation in an acutely manic patient. The accurate assessment of these issues can serve as a guide in determining treatment options and choices.