The aim of this study is to compare the antiplaque and antigingivitis efficacy of 0.25% lemongrass oil mouthwash and 0.2% chlorhexidine mouthwash in patients undergoing fixed orthodontic treatment, who are suffering from gingivitis.A total of 60 patients undergoing fixed orthodontic treatment with mild-to-moderate gingivitis were selected for the study. The patients were randomly divided into three groups of twenty each, that is, group I: 0.25% lemongrass oil mouthwash ( = 20); group II: 0.2% chlorhexidine mouthwash ( = 20); and group III: oral prophylaxis ( = 20). Baseline gingival index (GI) and plaque index (PI) were accessed followed by oral prophylaxis was done and the PI score was set to zero for all the patients. Patients were asked to swish their mouth with their respective mouthwashes and brushing (twice daily), that is, morning and before bedtime for 21 days. The PI and GI scores were recorded for all three groups on the 14th and the 21st days. The Bonferroni test was used for multiple comparisons of mean differences among variables after the application of the analysis of variance (ANOVA) test for comparison within the groups.A lower PI and the GI were found in the lemongrass oil mouthwash group by the 14th and the 21st days, respectively, a statistically significant difference ( < 0.001) compared to the chlorhexidine mouthwash group.The findings of the current study suggested that 0.25% lemongrass oil mouthwash has the potential to be used as a natural or herbal alternative to chlorhexidine mouthwash.It can be suggested that 0.25% lemongrass oil mouthwash may be a good herbal alternative to mouthwash containing 0.2% chlorhexidine gluconate.