Cinnamon is a spice obtained from the inner bark of several trees from the genus Cinnamomum that is used in both sweet and savoury foods. While native only to the island of Sri Lanka, cinnamon trees are now naturalized in South East Asia.
Cinnamon has been proposed for use as an insect repellent, although it remains untested. Cinnamon leaf oil has been found to be very effective in killing mosquito larvae. Of the compounds found in the essential oil from cinnamon leaves, cinnamyl acetate, eugenol, and anethole, and in particular cinnamaldehyde, were found to have the highest effectiveness against mosquito larvae.