Objectives: Inattention and hyperactivity identified during childhood often persist into adulthood in patients with attention deficit hyperactivity disorder (ADHD). Despite increasing number of studies on the efficacy of herbal medicine for ADHD in children, there are limited reports on its use for adult ADHD. This retrospective chart review aimed to investigate which herbs and formulas are utilized for treating adult ADHD in a real clinical setting.Methods: From November 2015 to July 2019, eight cases of adult ADHD were selected through a retrospective chart review in a Korean medical clinic. Adult ADHD was diagnosed according to the DSM 5 diagnostic criteria. Individualized herbal medicine formulas, including <i>Acori graminei rhizoma</i>, <i>Polygalae radix</i>, <i>Angelicae gigantis radix</i>, and <i>Bupleuri radix</i>, were prescribed to treat symptoms of adult ADHD.Results: After administration of herbal medicine, all patients showed improved scores on at least one part of the attention task. Of the four patients with elevated omission errors, three showed improvement, and one showed no change. Among the four patients with delayed response times, two improved to within the normal range. All five patients tested for working memory showed improvement in the number of forward correct responses and forward spans. Mild adverse events, such as loose stools and indigestion, were reported.Conclusions: Korean medicine treatment, including herbal medicine, acupuncture, and neurofeedback, may potentially be effective for decreasing omission errors and increasing working memory span in adult patients with ADHD. Controlled trials are needed to explore the efficacy and safety of these combined interventions for improving the symptoms of adult ADHD.