Topical 10% trans-cinnamaldehyde evoked pain, neurogenic inflammation, and hyperalgesia.

Co-administration of 40% L-menthol alleviated several of these established sensory symptoms.

L-menthol's counterirritant effect likely occurs through spinal inhibition and through peripheral antagonism.

Transient receptor potential cation channel M8 agonists could be useful as topical anti-hyperalgesics.