Introduction:The effect of Centaurea behen (Cb) on patients with systolic heart failure is not known academically. This study was conducted to evaluate the effect of Cb on improving the quality of life (QoL) and echocardiographic and biochemical blood parameters in patients with systolic heart failure.Methods:This study was a parallel double-blind, placebo-controlled randomized trial of 60 patients with systolic heart failure, was conducted from May 2018 up to August 2019. Intervention group received 150 mg twice daily Cb capsules for two months + Guideline directed medical therapy (GDMT), and control group received GDMT + placebo capsules for two months. The main aim of the present study were to assess the QoL based on the 6-minute walk test (6MWT) and the Minnesota living with heart failure questionnaire (MLHFQ). Independent T-test, paired T-test, and ANOVA were used for the analysis.Results:At the beginning of the present study there were no significant differences between study groups in terms of QoL and clinical results. After treatment, the average values of QoL based on MLHFQ and 6MWT instruments were significantly improved 15.5 and 36.18, respectively (P<0.05).Conclusion:Based on the MLHFQ, and 6MWT tests, the consumption of Centaurea behen root extract was associated with significant improvement in the quality of life of patients with systolic heart failure.