Abstract: Background and Objective: The 2-Butoxyethanol (2BE) rat model of human hemolytic disorders has been used widely to evaluate hemolysis and thromboembolic manifestations of different organs associated with sickle cell disease and β-thalassemia, however, studies on nitric oxide metabolism are far more scarce. This study investigated the effects of Solenostemon monostachyus leaf extract supplementation on 2BE-induced changes of inducible nitric oxide synthase (iNOS) levels and mRNA expression in female rats. Materials and Methods: Young female rats were divided into seven groups (Group A-G). All groups, except for group A, were exposed to 2BE. The treatments assignments were as follows, group C: Caffeic acid, group D: Ciklavit (herbal formulation of Cajanus cajan (L.) Mill sp.), group E-G: S. monostachyus (150, 200 and 250 mg kg–1 b.wt.), respectively. Liver and plasma iNOS levels, as well as mRNA expression of liver arginase-1 and iNOS, were assessed. Histopathological evaluation of the liver was also performed. The results were statistically analyzed for significant effects at p<0.05 using one-way analysis of variance (ANOVA). Results: Liver and plasma iNOS were significantly reduced (p<0.05) in group G, whereas liver iNOS was significantly increased (p<0.05) in group D-F compared with group B, iNOS mRNA expression was reduced, while arginase-1 mRNA expression was increased in group E-G compared with group B. Conclusion: Administration of S. monostachyus (250 mg kg–1 b.wt.) in the 2BE hemolytic rat model modulated plasma and liver iNOS levels and iNOS mRNA expression.