Anger is associated with various responses. Research on the neuroscience of anger has revealed that greater left than right frontal cortical activity is associated with angry approach-oriented responses, such as aggression, whereas greater right than left frontal cortical activity is associated with inhibited angry responses mixed with anxiety. In the current research, we extended these past studies by manipulating asymmetric frontal cortical activity using transcranial direct current stimulation and assessing its influence on ruminative responses to an interpersonal insult. Results revealed that self-reported rumination was greatest for participants who received a manipulated increase in relative right frontal cortical activity compared with those who received either a manipulated increase in relative left frontal cortical activity or sham stimulation. Taken together with past findings, the current results suggest that anger associated with greater relative left frontal cortical activity predicts approach-oriented aggressive action, whereas anger associated with greater relative right frontal cortical activity predicts inhibited rumination.