Effects of aromatherapy on anxiety: A meta-analysis of randomized controlled trials

The effects of aromatherapy on relieving anxiety were controversial. The purpose of this meta-analysis was to evaluate the effects of aromatherapy on anxiety in patients. We searched randomized controlled trials (RCTs) about aromatherapy on decreasing anxiety on PUBMED, WEB OF SCIENCE (January 1990 to October 2019), COCHRANE LIBRARY, EMBASE (updated to October 2019), and the Chinese databases CNKI, WanFang and CBMD. Twenty-five articles (Thirty-two trials) were included in this meta-analysis. The data of scale scores of Spielberger State–Trait Anxiety Inventory (STAI) were extracted. The pooled results demonstrated that inhalation and massage aromatherapy significantly decreased anxiety levels in different conditions. The weighted mean difference was -5.16 for State Anxiety Inventory (SAI) (95%CI: -5.78, -4.55, p<0.001) and -2.85 for Trait Anxiety Inventory (TAI) (95%CI: -3.95, -1.75, p<0.001). No side effects were mentioned in all of studies. The meta-analysis suggested that aromatherapy with different essential oils could alleviate anxiety significantly no matter the reason of anxiety. However, the proper dosage of essential oils needs further research.