Cinnamon for Ants: Does It Repel or Kill Ants, and How to Use It

TL;DR

• Cinnamon repels some ants for a short time, but it discourages them rather than stopping them. In lab tests, many ants still crossed a cinnamon line.
• Cinnamon does not kill ants in normal household use, and it never reaches the colony: the ants you see are only foragers.
• To use it, wipe the trail with soapy water, then sprinkle a thin, unbroken line of ground cinnamon across the entry point. Check it every day and refresh it.
• Don't breathe in cinnamon dust, wear gloves with cinnamon oil, and keep both away from children and pets.
• For the colony, use a slow-acting bait on the trail and leave it at least 2 weeks (Health Canada). Don't put cinnamon next to the bait.
• Need help? Get a quote from a recommended local exterminator through Pest Agent's referral form.

Cinnamon for ants sounds like the ideal kitchen fix: it smells pleasant, it is already in the cupboard and it seems harmless to sprinkle near food. In one student experiment, though, more than half of the fire ants tested still walked across a cinnamon barrier to reach a piece of melon, and the authors ranked cinnamon last of three repellents, behind baby powder and petroleum jelly.

That result does not make cinnamon useless, but it does set expectations. Every claim about cinnamon and ants rests on a few small lab tests, and no field trial in a real home has backed them up yet.

Does Cinnamon Repel Ants?

Cinnamon repels some ants for a short time, but the evidence comes from small lab studies, not from real homes. In those tests, ants slowed down or turned away at a ring or line of cinnamon, yet many still crossed it. Expect cinnamon to discourage ants, not to stop them.

Why Ants Avoid Cinnamon

Cinnamon is a spice made from the dried bark of Cinnamomum trees, and its strong smell comes mostly from a compound called cinnamaldehyde. Most cinnamon sold in Canadian grocery stores is cassia cinnamon, the most common type in North America (NCCIH). A University of Nevada Extension educator sums up the research this way: cinnamon acts on pests mainly as a repellent.

Ants find food by following scent trails laid down by other workers. According to UC IPM, wiping a trail with soapy water removes that scent. The idea behind cinnamon ants remedies is similar: a strong smell placed on or across the trail may cover it or make ants avoid the spot. That explanation is plausible, but no study has proven that cinnamon breaks ant pheromone trails.

What Lab Studies Show

Lab studies on cinnamon and ants are small and short. Two are worth knowing:

• Journal of Emerging Investigators, 2019. A student study tested 7 household products (chalk, cinnamon, ginger powder, lemon juice, rosemary powder, table salt and turmeric powder) by placing single ants inside a ring of each product. Cinnamon and lemon juice repelled ants best. Each trial lasted at most 240 seconds (4 minutes), so the study says nothing about how long cinnamon works in a real kitchen.
• InSTARs, Texas A&M, 2017. A student team put a barrier of cinnamon powder between red imported fire ants and a piece of melon. With no barrier, 18 of 20 ants reached the melon in 20 minutes. With cinnamon, 11 of 20 still crossed. Baby powder (4 of 20) and petroleum jelly (3 of 20) did much better, and the authors called cinnamon the worst of the three repellents tested.

In other words, cinnamon has a real but weak effect. None of the Health Canada or university extension pages reviewed recommend cinnamon for ant control.

Ground Cinnamon Versus Cinnamon Oil

Cinnamon oil repels ants better than ground cinnamon. In the 2019 lab study, the oil extracted from cinnamon worked better than the leftover cinnamon solids, which suggests the smell compounds do the work. The catch is that plant oils fade fast: UC IPM notes that plant-based products have limited residual activity against ants. Ground cinnamon also gets swept, wiped or blown away, so both forms need frequent reapplication.

Does Cinnamon Kill Ants?

Cinnamon does not kill ants in normal household use. A sprinkle of ground cinnamon or a cinnamon spray may push ants away, but you will not see the colony die off, and you should not expect it to.

Cinnamon Oil Toxicity in the Lab

Cinnamon oil can kill ants in a lab, at strengths you would not use at home. A 2008 study from Taiwan found that the leaf oil of a native cinnamon tree was 79.85% trans-cinnamaldehyde, and that the oil and the pure compound killed red imported fire ants at a 2% concentration in closed containers (Cheng et al., Bioresource Technology). Those were sealed lab tests, not kitchen floors, and no field trials were found.

Why Cinnamon Never Reaches the Colony

Cinnamon never reaches the colony because the ants you see are only foragers. The queen and most of the colony stay in the nest, often inside a wall, under a floor or outdoors. UC IPM explains that sprays kill only foraging ants without killing the colony and the queens. A repellent does even less: it sends the foragers somewhere else. Health Canada and UC IPM both point to slow-acting baits instead, because workers carry the bait back and share it with the whole nest.

When Cinnamon Can Make Ants Worse

Cinnamon can make some ant problems worse. Pharaoh ants, tiny yellowish ants that nest inside heated buildings, respond to repellents by splitting into new colonies, a process called budding (UF/IFAS, Alberta Health). Spreading cinnamon around their trails can turn one nest into several. If you see tiny pale ants in several rooms, skip repellents and read our guide to pharaoh ants first.

How to Use Cinnamon for Ants

Using cinnamon for ants works best as a barrier at the spots where ants enter, laid down after you wipe the trail. Follow these steps.

Find the Entry Points

Finding the entry points tells you where cinnamon will do the most good. Watch the ants for a few minutes and follow the trail back to where it starts: a gap under a door, a windowsill, a crack along a baseboard or a space around a pipe. Those are your targets, not the middle of the counter.

Clean the Trail

Cleaning the trail removes the scent other ants follow. Wipe the whole trail and the entry point with soapy water, as UC IPM recommends, then let it dry. Pick up crumbs and spills at the same time so there is nothing left to attract the ants back.

Ground Cinnamon Barrier

A ground cinnamon barrier is the simplest way to use cinnamon for ants:

1. Use ordinary ground cinnamon from your spice rack, or grind cinnamon sticks.
2. Sprinkle a thin, unbroken line across the entry point, such as a door threshold or a windowsill.
3. Keep the line continuous, since ants will walk through any gap.
4. Avoid spots where kids, pets or air drafts will scatter it.

Cinnamon Oil Cotton Balls

Cinnamon oil cotton balls give a stronger smell in a small spot. Put a few drops of cinnamon essential oil on a cotton ball and set it near the entry point or behind a cupboard where ants come in. Wear gloves, keep the oil off your skin, and place the cotton balls where children and pets cannot reach them.

Homemade Cinnamon Spray

A homemade cinnamon spray covers longer edges such as baseboards and window frames. Fill a spray bottle with water, add a small amount of cinnamon essential oil and the juice of a lemon, and shake well before each use. The lemon is not just for scent: in the 2019 lab study, cinnamon oil and lemon juice repelled ants better together than either one alone. Follow the dilution on the oil's label, test the spray on a hidden spot first, and never spray it on people, pets or plants. For other mixtures, see our guide to homemade ant killers.

Reapplying Cinnamon

Reapplying cinnamon is part of the method. The scent fades and the powder gets disturbed, so check your barriers every day and refresh them when the smell is gone or the line is broken. If ants are still coming in after a few days, cinnamon is not enough for your situation: switch to a bait.

Is Cinnamon Safe to Use Around Your Home?

Cinnamon is safe in food amounts, but cinnamon dust and cinnamon oil can irritate skin, eyes and lungs. "Natural" does not mean harmless, so use it with the same care as any other product.

Skin Irritation

Skin irritation is the main risk with cinnamon oil. According to the US National Center for Complementary and Integrative Health (NCCIH), some cinnamon oils and powders applied to the skin may irritate it. Wear gloves when you handle the oil and wash your hands afterwards.

Cinnamon Dust

Cinnamon dust should not be breathed in. A University of Nevada Extension educator warns that inhaled cinnamon can burn nasal and lung passages, and that it can burn plant leaves, so apply it only to soil if you use it near plants. Sprinkle it gently instead of shaking it into the air.

Children and Pets

Children and pets should be kept away from cinnamon barriers and cinnamon oil. Kids and pets can walk through the powder, lick it or knock over a cotton ball soaked in oil. Concentrated essential oils are a concern for cats and dogs, so store the bottle out of reach and ask your veterinarian before using any oil around your pet. For options that are labelled for use around animals, see our guide to pet-safe ant killers.

Homemade Pesticides in Canada

Homemade pesticides, including cinnamon sprays, are not tested in Canada. Health Canada warns that homemade pest recipes are not scientifically tested for their effects on health and the environment, may not work because they are not tested for effectiveness, and that overexposure can be harmful, especially to children. Registered products carry a PCP (Pest Control Products) number on the label, which shows Health Canada has assessed them.

What Works Better Than Cinnamon for Ants?

Slow-acting ant baits work better than cinnamon because worker ants carry them back to the nest and feed them to the queen. Pair baits with good sealing and food storage, and save repellents like cinnamon for doorways you want to block.

Ant Baits

Ant baits are the most reliable way to get rid of an ant colony. Health Canada says baits work slowly so workers can carry the poison back to the whole colony, and advises placing bait stations directly on ant trails, out of reach of children and pets, leaving them for at least 2 weeks and not spraying the same ants while you bait. The City of Calgary notes that slow-acting baits, such as boric acid baits, eliminate the colony. Do not put cinnamon next to a bait: it can steer ants away from the food you want them to take. For tested products, see our picks for the best ant killer.

Diatomaceous Earth

Diatomaceous earth is another non-chemical option you can use where ants travel. Health Canada suggests placing it in cracks, notes that it is non-toxic to humans and pets, and warns not to inhale the dust when you apply it. Our guide to diatomaceous earth for ants explains how to apply it.

Other Home Remedies

Other home remedies work much like cinnamon: they repel or kill the ants they touch, not the colony. Vinegar and peppermint oil are other strong-smelling repellents, and dish soap mixed with water is a popular contact spray. Read our guides on whether vinegar kills ants, peppermint oil for ants and using dish soap on ants to compare.

Sealing Entry Points

Sealing entry points keeps new ants from coming in once the colony is under control. Health Canada recommends sealing visible cracks in foundations and walls and caulking baseboards and crevices. Do it after baiting, so you do not cut the ants off from the bait.

Food Storage

Food storage removes the reason ants come inside. Keep sugar, cereal and snacks in sealed containers rather than open bags, wipe counters and floors, and empty the garbage often. Health Canada also suggests setting your pet's food dish inside a shallow dish of water, because ants cannot swim across it.

When to Call a Pest Control Professional

Calling a pest control professional makes sense when home remedies and baits have not worked after a few weeks, when ants show up in several rooms, or when you find piles of sawdust, a sign of carpenter ants damaging wood (Health Canada). Carpenter ants need the nest treated, not repelled. Learn the signs of carpenter ants, or get a quote from a recommended local exterminator through Pest Agent's referral form.