Analgesic Effects of Olfactory Stimulation: A Systematic Review of Clinical and Experimental Evidence

Pain perception is a multidimensional process encompassing sensory, affective, and cognitive components. In recent years, accumulating evidence suggests that olfactory stimulation can modulate pain perception through neurophysiological and emotional mechanisms. However, systematic understanding of how olfactory processing contributes to analgesia across different experimental and clinical contexts remains limited. This review aims to provide an integrative overview of current evidence regarding the role of olfactory pathways in pain modulation, summarizing findings from human and animal studies that investigated the analgesic potential of volatile compounds. A systematic literature search was conducted across PubMed, Web of Science, OVID, Cochrane Reviews, Embase, CNKI, and WanFang databases. A total of 4360 records were retrieved, screened for relevance, and refined to 147 studies, including 138 human-based and 9 animal-based investigations. Lavender, peppermint, chamomile, bergamot, and citrus-derived oils were most frequently associated with analgesic outcomes. Olfactory stimulation was found to modulate pain via central integrative circuits involving affective, autonomic, and sensory processing, engaging conserved pathways that support descending pain inhibition. Olfactory stimulation by specific flavor and fragrance compounds holds translational potential for non-pharmacological pain management. Nevertheless, methodological standardization and mechanistic validation are necessary to advance this emerging field.