Background & objectives: Ritalin is one of the drugs used in the treatment of attention-deficit/hyperactivity disorder (ADHD). This study aimed to investigate the comparative effect of Ritalin with grape seed extract on passive avoidance learning in adult male rats.

Methods: In this experimental study, 40 adult male Wistar rats divided randomly into 5 groups of 8 rats including control, sham and three experimental groups. The control group received no treatment. The sham group received 1 ml of distilled water per day. At the same time the experimental groups received 100 mg/kg grape seed extract, 1 mg/kg Ritalin or 100 mg/kg grape seed extract together with 1 mg/kg of Ritalin by gavage for 28 days. For measuring the amount of avoidance learning, Shuttle box was used. Data analyzed by ANOVA and consistent Tukey's tests using SPSS-18 software and p>0.05 considered as significant.

Results: The results showed that Ritalin decreases the passive avoidance learning, while the grape seed extract alone or together with Ritalin increases passive avoidance learning.

Conclusion:  The outcome of this research shows that taking Ritalin leads to decreasing passive avoidance learning. However, the simultaneous taking Ritalin with grape seed extract inhibits the Ritalin effect and increasing the learning.