Cinnamon has become a popular household remedy, widely touted as a natural way to deter ants from entering a home. This belief is so widespread that it is one of the most frequently attempted DIY pest control methods. The question remains whether this fragrant spice provides a truly effective barrier against invading ant colonies.
Why Cinnamon is Thought to Repel Ants
The primary component that gives cinnamon its ant-repelling properties is cinnamaldehyde, a naturally occurring organic compound highly concentrated in the essential oil. Ants rely heavily on chemical signals called pheromones, which act like roadmaps guiding them to food sources and back to the colony. When an ant finds food, it lays a chemical trail that other ants follow, organizing the foraging process.
The strong aroma of cinnamaldehyde is believed to overwhelm and disrupt these pheromone trails. This disruption causes a “sensory blackout,” making it impossible for ants to follow their intended path or communicate effectively. Disoriented ants lose track of their food source and are forced to abandon the treated area. This chemical interference creates an environment ants find intolerable, encouraging them to seek an alternative location.
Methods for Applying Cinnamon as a Deterrent
Home application of cinnamon typically involves two main forms: the powdered spice and the concentrated essential oil. Ground cinnamon powder is used to create a physical and aromatic barrier at known entry points. This involves sprinkling an uninterrupted line of powder along cracks, window sills, door frames, and baseboards where ants are seen entering the structure. The goal is to make the threshold impassable for the insects.
A more potent method involves using cinnamon essential oil, which contains a higher concentration of cinnamaldehyde. The oil can be diluted with water to create a spray mixture, often at a ratio of 10 to 20 drops per cup of water. This solution is sprayed directly onto ant trails and entry points, offering increased potency and a longer-lasting scent than powder. Alternatively, a few drops of concentrated oil can be applied to cotton balls and strategically placed where ant activity is observed.
Scientific Evidence on Effectiveness
Scientific research confirms that concentrated cinnamon extracts and essential oils possess repellent and insecticidal properties against some ant species. Studies indicate that cinnamaldehyde can reduce ant activity in treated areas by 70 to 95% within 24 hours in laboratory settings. This effect is due to the compound’s ability to interfere with the ants’ nervous systems, acting as a powerful irritant and temporary deterrent.
However, household-grade cinnamon powder is significantly less effective than the highly concentrated essential oil. While the powder may temporarily confuse ants, it rarely provides a permanent solution because the active compound degrades over time. Cinnamon works as a repellent, not an exterminator, meaning it pushes ants to find a new path rather than eliminating the source of the infestation. Since cinnamon does not eliminate the queen or the colony, the temporary barrier requires frequent reapplication every one to three days.
Safety and Quality Considerations
When using cinnamon, particularly the essential oil, homeowners should be aware of potential safety considerations for people and pets. Concentrated cinnamon oil can cause skin irritation or respiratory issues if not handled carefully. It is particularly toxic to household pets, especially cats, who lack the liver enzymes necessary to properly metabolize the phenolic compounds, like cinnamaldehyde, found in the oil. Even passive exposure from a diffuser can be hazardous to felines.
A distinction must also be made between the two main types of cinnamon available commercially: Ceylon and Cassia. Most cinnamon sold in grocery stores is Cassia, which contains higher levels of a naturally occurring compound called coumarin. Cassia cinnamon can contain up to 30 times more coumarin than Ceylon cinnamon, which is a mild liver toxin in large amounts. Choosing Ceylon (often called “true cinnamon”) is a safer option for applications where the spice might be accidentally ingested by children or pets.