Objective: This feasibility study examined the effects of a particular Traditional Chinese Medicine (TCM) herbal formula on attention-deficit/hyperactivity disorder (ADHD) and related problem behaviors.Design: A total of 79 participants aging 6-12 years consumed a granulated TCM herbal formula twice daily over a period of 3 months and underwent assessments at months 0, 3, and 6. Changes in ADHD symptoms and related behaviors were measured using the ADHD rating scale-IV (ADHD-RS-IV), child behavior checklist (CBCL), children's global sssessment scale (CGAS), as well as the clinical global impressions-severity (CGI-S) and improvement (CGI-I) scales.Results: Repeated measures mixed model analyses revealed significant differences in scores across time on all ADHD-RS-IV and CBCL subscales as well as on the CGAS, CGI-S, and CGI-I scales. Pairwise comparisons between months 0 and 3 as well as months 0 and 6 indicated significant improvements in scores. Scores also did not differ significantly between months 3 and 6. The results may suggest that this particular TCM formula possesses potential therapeutic qualities in the treatment of ADHD. Furthermore, changes in ADHD symptoms generally appear to be stable 3 months after discontinuation. However, these findings could also be attributed to placebo effects as well as reporting biases.Conclusion: This particular TCM formula may prove to be a useful adjunctive treatment for children with ADHD, and randomized controlled trials need to be conducted to evaluate its efficacy.