Attention-deficit/hyperactivity disorder (ADHD) has become one of the most commonly diagnosed disorders of childhood. Prevalence of the condition has increased from 6.1% in 1998 to 10.2% in 2016 in the United States. Standard treatment recommendations for ADHD include both pharmacological and behavioral therapies which mostly ignore the majority of the causes. Focusing on treatments with more tolerable side effect profiles than stimulants could also be helpful for treatment compliance. One potential treatment option that has been slowly building evidence of efficacy is the supplementation of oligomeric proanthocyanidins (OPCs). OPCs are found in fruits, vegetables, and other plants, some of which have a long history of medicinal use.