Title: Effect of Pyridoxine as Add-on Therapy with Standard Treatment in Obsessive Compulsive Disorder Patients: A Randomized, Double-Blind, Placebo-Controlled Trial Purpose of the study: This study aims to examine the effect of Pyridoxine with standard treatment in Obsessive Compulsive Disorder patients. Method: It will be a prospective type of interventional study to to assess the effects of Pyridoxine along with standard treatment in OCD patients. The study will be conducted in the Department of Pharmacology,BSMMU and Department of Psychiatry, BSMMU, from September 2022 to July 2024. A total of 76 OCD patients will be selected according to inclusion and exclusion criteria. The patients will be divided randomly into 2 groups: group A and group B. Group A will consist of 38 patients who will receive tablet pyridoxine 25 mg twice daily with standard treatment and group B would consist of 38 patients who will receive placebo twice daily along with standard treatment for 8 weeks. To see the effects of pyridoxine, Yale-Brown score of obsessive-compulsive disorders (Y-OCD) would be assessed by Yale-Brown Obsessive Compulsive Scale (Y-BOCS) at baseline (before pyridoxine administration) and 8 weeks after intervention(after pyridoxine administration). Biochemical parameters of oxidative stress markers such as plasma malondialdehyde (MDA), RBC glutathione (GSH) would be performed at baseline (before pyridoxine administration) and 8 weeks after intervention. Ethical consideration: The study will follow the principles of the Declaration of Helsinki and of the World Medical Assembly. Patients will be informed about the study in easy language and then informed consent will be taken. This study has no potential risk to the patients. Confidentiality will be strictly maintained.