A narrative review of aromatherapy: Mechanisms and clinical value in physiological and psychological regulation

OBJECTIVE: This narrative review comprehensively explores the physiological mechanisms, psychological effects, and theoretical hypotheses of aromatherapy, along with its applications in clinical practice. BACKGROUND: Aromatherapy, utilizing plant-derived essential oils, is a significant component of complementary medicine widely implemented in clinical practice. Recent research advancements demonstrate its regulatory effects physiologically and psychologically, showing clinical potential for nervous, circulatory, and immune systems. METHODS: Searches were conducted in the China National Knowledge Infrastructure (CNKI), PubMed, and Web of Science databases to identify relevant studies published in recent years. Based on the retrieved literature, the biological effects of aromatherapy on the nervous, circulatory, and immune systems are summarized in this review. DISCUSSION: From a physiological perspective, olfactory molecules can enter the bloodstream either through the olfactory system or via transdermal absorption, subsequently modulating the immune system. They have been shown to inhibit the release of pro-inflammatory cytokines, enhance the expression of anti-inflammatory factors, scavenge free radicals, reduce cellular oxidative stress, and mitigate systemic inflammatory responses. Regarding psychological effects, aromatherapy modulates the secretion of neurotransmitters such as gamma-aminobutyric acid (GABA), thereby alleviating anxiety. Additionally, it influences emotional states and cognitive functions by stimulating the olfactory system, which interacts with the limbic system and brain regions involved in emotional processing. Specific essential oils like lavender demonstrate substantial evidence for analgesic and anxiolytic effects, while Rosmarinus officinalis shows efficacy in enhancing cognitive function. The review particularly focuses on its mechanisms and clinical applications in pain relief, anti-inflammatory activity, antioxidative properties, antidepressant and anxiolytic effects, and adjunctive care. CONCLUSION: Future research should prioritize elucidating mechanisms of action, bioavailability, and long-term safety to fully uncover its therapeutic potential.