Background:
To determine the efficacy and safety of Vernonia cinerea (L.) Less. for smoking cessation using a systematic review and meta-analysis approach.

Methods:
Data sources: Nine databases were searched through April 2017.
Study selection: Randomized controlled trials that reported the clinical effect of V. cinerea. for smoking cessation were included.
Data extraction: Important data and outcomes were extracted by two independent researchers. Study quality was assessed using the Cochrane risk of bias tool and JADAD score.

Results:
Data synthesis: Five trials with 347 active smokers were included. Two trials were rated as low risk of bias in all domains while others were rated as some concerns. V. cinerea treatment group was associated with significant cessation rate higher than that in the control group with no evidence of heterogeneity for both continuous abstinence rate (CAR) (week 8 risk ratio (RR): 1.69, 95% CI [1.00, 2.86]; week 12 RR: 2.18, 95% CI [1.17, 4.04]) and 7-day point prevalence abstinence rate (PAR) (week 8 RR: 1.51, 95% CI [1.01, 2.27]; week 12 RR: 1.93, 95% CI [1.24, 2.99]) at week 8 and 12, respectively. There was no significant difference of all adverse events between treatment and control groups.

Conclusions:
This comprehensive systematic review and meta-analysis suggests that V. cinerea might be considered as a potential alternative for smoking cessation treatment. Further well-design RCTs of standardized V. cinerea compared with standard treatment should be conducted to strengthen this evidence.