Occurring naturally as predominantly the trans (E) isomer, it gives cinnamon its flavor and odor.

[2] This pale yellow, viscous liquid occurs in the bark of cinnamon trees and other species of the genus Cinnamomum.

[3] Cinnamaldehyde was isolated from cinnamon essential oil in 1834 by Jean-Baptiste Dumas and Eugène-Melchior Péligot[4] and synthesized in the laboratory by the Italian chemist Luigi Chiozza in 1854.

[7] Deamination of L-phenylalanine into cinnamic acid is catalyzed by phenylalanine ammonia lyase (PAL).

The most obvious application for cinnamaldehyde is as flavoring in chewing gum, ice cream, candy, e-liquid and beverages; use levels range from 9 to 4,900 parts per million (ppm) (that is, less than 0.5%).

Almond, apricot, butterscotch, and other aromas may partially employ the compound for their pleasant smells.

[18] A concentration of 29 ppm of cinnamaldehyde kills half of Aedes aegypti mosquito larvae in 24 hours.

Cinnamyl alcohol similarly occurs naturally and has the odor of lilac but can be also produced starting from cinnamaldehyde.

[25] Cinnamaldehyde may cause allergic contact stomatitis in sensitised individuals, however allergy to the compound is believed to be uncommon.

Cinnamaldehyde is a dietary antimutagen that effectively inhibits both induced and spontaneous mutations.