This disclosure relates to dosage forms containing an enantiomerically enriched or pure bupropion such as enantiomeric excess of (S)-bupropion, enantiomerically enriched (S)-bupropion, or enantiomerically pure (S)-bupropion and methods of using these dosage forms. These dosage forms may be administered to human beings in a reduced amount as compared to the amount of racemic bupropion that would be administered in the same situation.