An overview of the evidences of herbals for smoking cessation.

BACKGROUND Despite availability of several therapeutic options for smoking cessation, their usages are limited due to high cost and adverse effect profiles. Recently, more attention has been paid to investigating herbals for smoking cessation. OBJECTIVES To review relevant evidences on the efficacy and safety of herbals for smoking cessation. METHODS We searched clinical studies evaluating herbals use for smoking cessation from Medline, EMBASE, CINAHL, Cochrane CENTRAL, PsychINFO, AMED, WHO Trial registry, Thai dissertation database, and other databases from its inception to October 2012. Studies are restricted to only English or Thai. RESULTS A total of 7 studies met inclusion criteria; 6 studies were randomized trial (RCT) evaluating variety of herbals. Three RCTs evaluated oral St. John's wort (SJW) extract (N=289), 2 RCTs evaluated oral mix-herbal tea (N=164), and 1 RCT evaluated inhaled aromatic black pepper (N=48). The other study was a non-randomized controlled trial evaluating oral SJW extract among 24 smokers. All interventions were given in a range of 1 week before starting the study and continued up to 14 weeks. Smoking cessation was measured with various methods including the number of cigarettes per day, abstinence rate, expired CO level, and urine cotinine level. Follow-up duration ranged from 3-h session to 6-months period. Evidences of SJW indicated low percentage in abstinence rate for smoking and its effectiveness was not significantly different from placebo. Studies of mix herbal tea showed a statistically significant effectiveness, compared to placebo, in reducing the number of cigarettes per day, craving scale, and total withdrawal scale but not urinary cotinine excretion. Essential oil of black pepper with a hollow plastic tube significantly reduced craving at 3-h session. CONCLUSION Evidence supporting the role of complementary medicines as an anti-smoking is limited. Further research in this field would benefit from the standardization of herbals products to implement on standard interventions and outcome measurement for smoking cessation.