Objectives: To evaluate the effects of curcumin mouthwash on oxidative stress levels in patients undergoing fixed orthodontic treatment by assessing the levels of 8- hydroxydeoxyguanosine in GCF. Design and Setting: 50 patients (27 females and 23 males) participated in the study and were randomly allocated between two groups. Group 1 - subjects who were given curcumin mouthwash and toothpaste; group 2 – subjects who acted as control group (only toothpaste). Methods: The levels of 8-hydroxydeoxyguanosine from GCF samples of patients were used to assess the oxidative stress levels of the periodontiumat three time periods: pretreatment (T0),3 months of treatment (T1) and 6 months of treatment (T2). Kruskal Wallis test was used to test the null hypothesis that there was no difference in biomarker levels across the three time periods for both experimental and control group followed by Dunn’s post hoc analysis.The non-parametric Mann Whitney U test was used to perform the comparisons between the experimental and control group during the three time periods (P <0.05). Results: The median value for 8 hydroxydeoxyguanosine level was lowest when taken at the 6 months interval (8.24 ng/L; IQR=6.94-9.84) in experimental group (Curcurmin mouthwash + toothpaste group). The results of Mann-Whitney U test showed that there was statistically significant difference between experimental (Curcurmin mouthwash + toothpaste) and control groups (Toothpaste group) during the 6th month. Conclusion: Curcumin mouthwash can serve as an effective way of reducing the oxidative stress levels in patients undergoing fixed orthodontic treatment.