The Best Carpenter Ant Killers of 2024 to Protect Your Wood Structures

Carpenter ants are troublesome insects that chew through wood, which may include the framework of a home. Eliminate infestations and prevent new colonies from forming with a carpenter ant killer.

Best Overall

Bag of Safer Brand Diatomaceous Earth Ant & Insect Killer

Safer Brand Diatomaceous Earth Ant & Insect Killer


Bottle of Eco Defense Biobased Home Pest Control Spray

Eco Defense Biobased Home Pest Control Spray

Best Bang for the Buck

Bottle of Mighty Mint Insect & Pest Control Concentrate

Mighty Mint Insect & Pest Control Spray

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Although many ant varieties can cause problems in a home, few are as potentially damaging as the carpenter ant. This aptly named species builds its nest by tearing tunnels through wood. If left unchecked, this can wreak havoc on a building—resulting in thousands of dollars in structural damage. This is why it’s crucial to find a suitable solution that will eliminate the whole colony for good.

Carpenter ant killers offer a cost-effective alternative to hiring a professional exterminator to rid one’s home of destructive ants. These products come in various forms: sprays that kill on contact; liquid baits that attract and infect worker ants, which carry the poison back to their parent colony; and granules applied outdoors to prevent ants from getting inside. 

We recommend the Safer Brand Diatomaceous Earth Ant & Insect Killer as our top pick for its nontoxic formula; fast-acting 48-hour working time; and nonexpiring chemical composition. There are other effective ant killer options on the market, including the Terro Liquid Ant Killer or the Advion Ant Gel Bait. However, they do not meet our sustainability guidelines and are not recommended in our top picks due to their potentially harmful ingredients and negative impact on the environment.

Use this buyer’s guide to find important considerations to keep in mind when shopping and recommendations for effective products to find the best carpenter ant killer for a pest problem.

  1. BEST OVERALL: Safer Brand Diatomaceous Earth Ant & Insect Killer
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  2. RUNNER-UP: Eco Defense Biobased Home Pest Control Spray
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  3. BEST BANG FOR THE BUCK: Mighty Mint Insect & Pest Control Spray 
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  4. BEST BAIT GEL: Combat Max Indoor and Outdoor Ant Killing Gel Bait
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  5. BEST GRANULAR: Advance Carpenter Ant Bait 
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  6. BEST SPRAY: Orange Guard Home Pest Control
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  7. BEST OUTDOOR: Wondercide EcoTreat Outdoor Pest Control Spray
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  8. BEST INDOOR: Syngenta Optigard Ant Bait Gel
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  9. BEST ROACH & ANT KILLER: Garden Safe Diatomaceous Earth Crawling Insect Killer
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Pack of Terro liquid ant baits on a shelf

Before You Buy Carpenter Ant Killer

While there are effective solutions on the market to get rid of carpenter ants in houses, it’s important to understand the risks associated with these products. Many insecticides contain such active ingredients as borax and hydramethylnon. These chemicals can cause vomiting and diarrhea or even kidney failure and seizures if ingested or inhaled. Borax is also unkind to the planet as it uses boron, extracted through strip mining, a process that leaves a large environmental footprint. Many chemicals commonly found in pesticides also harm aquatic organisms as well as beneficial insects, including honey bees, ladybugs, and spiders. 

This guide focuses on products that are effective at controlling carpenter ant populations while leaving a much smaller footprint on the environment. They include products that use natural ingredients such as diatomaceous earth and essential oils, as well as insect repellents that won’t harm environmentally beneficial insects. 

How We Chose the Best Carpenter Ant Killers

A good carpenter ant killer should be an effective and safe way to eliminate these wood-destroying insects from the home. With that in mind, we selected products with active ingredients proven to kill ants without harming people, pets, or the planet. All of our selections are deemed safe by the Environmental Protection Agency (EPA). Some are also USDA Certified Biobased, meaning they have ingredients derived from plants and other renewable materials and contain no harsh synthetic chemicals. 

In addition to insecticides (i.e., insect killers), we also chose products that repel pests, reducing the impact on the environment by not killing beneficial insects. Where possible, we chose eco-friendly products containing all-natural ingredients that are nontoxic to people and pets. 

Our Top Picks

The lineup below features pest control products capable of killing carpenter ants that make their way into a home; some may also be able to annihilate an entire ant colony in a matter of days. Our selections are effective while minimizing environmental impact. 

Best Overall

Safer Brand Diatomaceous Earth Ant & Insect Killer

Product Specs 

  • Type: Powder
  • Active ingredient: Diatomaceous earth 
  • Quantity: 4 pounds


  • Fast-acting formula kills an entire colony in under 48 hours for excellent efficiency 
  • Doesn’t expire; keeps for years so buyers will only have to purchase once for small-scale infestations 
  • Nontoxic formula; suitable for indoor or outdoor use and homes with children and pets 


  • Powder form can get messy if used in a bustling household 

For those looking to end their ant problem without introducing harmful chemicals into the environment, diatomaceous earth is an excellent option. This natural substance, which is safe for indoor and outdoor use, consists of the fossilized remains of microscopic aquatic organisms; it infiltrates the exoskeletons of ants, dehydrating them from the inside out and killing them in about 48 hours.

Diatomaceous earth is also an effective means of killing bed bugs, cockroaches, fleas, and other creepy crawlers. This product is not harmful to humans or animals, providing a safe pest solution for homes with pets and young children. Safer Brand’s diatomaceous earth comes in 4-pound bags. 

Get the Safer Brand carpenter ant killer at Amazon or Walmart.


Eco Defense Biobased Home Pest Control Spray

Product Specs 

  • Type: Spray
  • Active ingredients: Sodium lauryl sulfate, geranium oil, peppermint oil 
  • Quantity: 16 ounces


  • Kills on contact for fast-acting carpenter ant extermination; works in gardens, food handling areas, closets, crawl spaces, and cracks 
  • Creates a barrier that repels pests and prevents infestations from happening 
  • Uses ingredients safe for humans and the environment; suitable for indoor and outdoor use


  • Smaller quantity compared to other carpenter ant treatments; may require multiple purchases for larger infestations 

With ingredients that are safe for humans and the environment, Eco Defense is an effective and safe way to rid one’s home of carpenter ants and other pests. Eco Defense uses geranium and peppermint essential oils to kill ants along with fleas, earwigs, gnats, scorpions, and a host of other pests. 

In addition to killing on contact, it also serves as a preventative to repel insects. The formula, which is USDA Certified BioBased, is considered safe for use indoors and outdoors with less concern about coming into contact with people or pets. Though effective, Eco Defense is one of the more expensive options on the market. 

Get the Eco Defense carpenter ant killer at Amazon, Eco Defense, or Walmart.

Best Bang for the Buck

Mighty Mint Insect & Pest Control Spray

Product Specs 

  • Type: Spray
  • Active ingredient: Peppermint oil
  • Quantity: 1 gallon


  • Safe for people, pets, and the environment; won’t hurt beneficial insects
  • Very easy to apply; comes with a built-in sprayer for applying in the home, in gardens, garages, storage areas, pools, and patios
  • Pleasant smell emitted after application; will not leave harsh smells in the house like most chemical carpenter ant killers


  • Does not work on some pest varieties; may not be ideal for some users’ needs 

Mighty Mint is an affordable yet effective means of repelling carpenter ants without harmful chemicals, and it imparts a pleasant, natural aroma in the process. It relies on peppermint oil, which has a high concentration of menthol, to deter and drive off spiders, ants, and a variety of other pests effectively. Peppermint is nonlethal, so while it won’t kill ants, it won’t harm beneficial insects either. It is also safe to use indoors around people and pets. 

Get the Mighty Mint carpenter ant killer at Amazon or Walmart.

Best Bait Gel

Combat Max Indoor and Outdoor Ant Killing Gel Bait

Product Specs 

  • Type: Gel
  • Active Ingredient: Fipronil
  • Quantity: 27 grams


  • Concentrated formula; very small amount needed to kill the entire colony 
  • Doesn’t make a mess like other carpenter ant killers; simply apply and forget 
  • Fast acting; kills the entire colony in just a few days


  • Fipronil can harm the environment and should be kept away from people and pets

Combat incorporates crosshairs into its logo for good reason: The ant-killing gel comes in a syringe for precise, targeted application in entry points like cracks and crevices. 

While the active ingredient, fipronil, is not considered to be environmentally safe and should be kept away from people and pets, only a small amount in a tiny space is required to get the job done—and such a small amount is unlikely to have an impact on the wider world. The applicator also prevents the messy overspray that other products can cause, making it easier to limit its application to a small crack, minimizing potential contact with people, pets, and the planet. 

Combat gel is capable of knocking out an entire colony because all it takes is one ant to come into contact with the gel and carry it back to the nest. Within a few days, this ant bait gel will attract ants and kill the entire colony. 

Get the Combat carpenter ant killer at Amazon, Ace Hardware, Lowe’s, The Home Depot, or Walmart.

Best Granular

Advance Carpenter Ant Bait

Product Specs 

  • Type: Granular
  • Active Ingredient: Abamectin B1
  • Quantity: 8 ounces 


  • Versatile formula; suitable for a wide variety of ants and can be used both indoors and outdoors
  • Covers areas large and small; 1.8 ounces of product can cover 5,000 square feet 
  • The compact container is easy to store in garages, sheds, or cupboards 


  • Some users have reported that this option emits a foul or fishy smell 
  • Apply as directed and store far from any household pets

Made with a wide variety of attractants, this Advance carpenter ant bait is the perfect solution for common ant problems. These granulated baits for carpenter ants are capable of eliminating carpenter, acrobat, Argentine, bigheaded, fire, harvester, pharaoh, and other ant varieties for complete control over these pests. It can also be used indoors and outdoors for excellent versatility. 

Though these gel baits come in a compact 8-ounce container, just 1.8 ounces of product covers over 5,000 square feet. However, this insecticide may cause mild symptoms in dogs and cats if exposed to ample amounts. 

Get the Advance carpenter ant killer at Amazon or Walmart.

Best Spray

Orange Guard Home Pest Control

Product Specs 

  • Type: Spray
  • Active ingredient: Orange peel extract
  • Quantity: 32 ounces


  • Safe for use around food, children, and pets and will not harm the environment
  • Works as pesticide as well as a repellent for added user-friendliness
  • Ready to use as soon as it arrives; suitable for small-scale infestations 
  • Affordable compared to other carpenter ant killers on the market


  • Needs more frequent applications than other pesticides; small quantity is not suitable for large-scale infestations 

An inherent problem with most spray pesticides is that the wide release of the product can cause tiny particles to become airborne—a hazard if they contain harsh or toxic chemicals. That’s not an issue with Orange Guard carpenter ant spray, which uses orange peel extract as its active ingredient. 

This formula makes Orange Guard one of very few pesticides appear on the FDA’s Generally Recognized as Safe List in regard to food. This rating makes Orange Guard safe to use in the kitchen and around people and pets. It also appears on the Organic Review Institute’s list of organic products. Orange Guard works as a pesticide when sprayed directly on insects and also as a repellent. 

Get the Orange Guard carpenter ant killer at Amazon or Walmart.

Best Outdoor

Wondercide EcoTreat Outdoor Pest Control Spray

Product Specs 

  • Type: Concentrate
  • Active ingredients: Cedarwood oil, sesame oil, sodium lauryl sulfate
  • Quantity: 32 ounces


  • Easy to apply via a garden hose; ready-to-use hose attachment built-in for convenience 
  • Uses essential oils as active ingredients rather than harsh chemicals
  • Kills on contact; can be used for large and small infestations 
  • Works as a killer and deterrent; repels insects for up to 45 days


  • May kill beneficial insects if applied in their immediate vicinity 

Pesticides designed for outdoor use aren’t generally an option where kids and pets are often at play. These products also pose a greater environmental risk than pesticides applied inside the home. Wondercide, however, is a nontoxic option that relies on a mix of natural essential oils, including sesame and cedarwood, to kill and repel ants, mosquitoes, fleas, and ticks without harming beneficial bees.

Wondercide comes in a spray bottle that attaches to a standard garden hose. The concentrated formula is automatically diluted as water from the hose passes through the attachment for easy application. A 32-ounce bottle can cover 5,000 square feet, and each treatment lasts between 30 and 45 days, though the manufacturer does recommend a second application within 2 to 10 days.

Get the Wondercide carpenter ant killer at Amazon.

Best Indoor

Syngenta Optigard Ant Bait Gel

Product Specs 

  • Type: Gel 
  • Active ingredient: Thiamethoxam
  • Quantity: 1.6 ounces (per bottle)


  • Precision applicator is suitable for application into small cracks and crevices 
  • Lasts for over 14 days after applied; kills the workers, brood, and the queen 
  • Nonstaining and no-odor formula can be applied to most surfaces away from food 


  • Does not work as a harvester, pharaoh, or fire ant killer 
  • Small quantity per bottle; may not be suitable for whole-house infestations 
  • The manufacturer does not provide a time frame for when an entire colony will be gone 

When ants find their way indoors, kitchens and eating areas can be easily infiltrated. This option from Syngenta is capable of killing off indoor Argentine, carpenter, and ghost ant infestations safely and with precision. 

This option is highly attractive to ants; stays active for 14 days; and disperses the poison to the entire colony, killing workers, brood, and the queen. Each 1.6-ounce bottle of ant killer is nonstaining, leaves no odor behind, and comes with a precision applicator for tiny cracks and crevices where ants tend to linger. However, the manufacturer cautions not to use this gel near food or where users tend to eat. 

Get the Syngenta carpenter ant killer at Amazon.

Best Roach & Ant Killer

Garden Safe Diatomaceous Earth Crawling Insect Killer

Product Specs 

  • Type: Powder
  • Active ingredient: Diatomaceous earth
  • Quantity: 4 pounds


  • Safe for use around food, pets, and people; can be used indoors and outdoors
  • Effective for destroying any ant species’ nests as well as cockroaches, silverfish, beetles, and more 
  • Has no shelf life and will work indefinitely when kept clean and dry


  • Powder can be messy if used indoors in bustling households 

This insect killer will take out roaches and carpenter ants in homes without creating a hazard for the environment, people, or pets. It uses diatomaceous earth, which kills insects by infiltrating the cracks in their exoskeleton and then dehydrating them. To destroy a nest, use a squeeze bottle to blow diatomaceous earth into moist wood or tree stumps where carpenter-ant infestations typically start. To kill insects outside the nest, sprinkle the powder directly onto ant traffic areas. 

Garden Safe kills within a day of contact. It’s nontoxic and safe for use in vegetable gardens. In addition to ants, Garden Safe will kill cockroaches, silverfish, beetles, and other insects. 

Get the Garden Safe carpenter ant killer at Amazon or Lowe’s.

Or, DIY Your Own Carpenter Ant Killer

There are several homemade remedies that are safe, cheap, easy to make, and effective against ants—and they use common household products likely to already be on hand in the kitchen cupboard. 

  • Spray a one-to-one solution of white vinegar and water on ants to kill them, and then use a paper towel to wipe them up. The lingering smell, which is not detectable to humans, will also repel other ants. 
  • To take out carpenter ant nests, try pouring a pot full of boiling water over it. This will flood the nest and kill ants on contact. 
  • Kill ants on contact by sprinkling cornstarch over them, then pouring water on top to trap possible escapees. Wipe them up with a paper towel.

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What to Consider When Choosing Carpenter Ant Killer

Understanding how the different types of pesticides and repellents work is key to addressing a carpenter ant problem. Ahead, learn more about granules, sprays, and gels, as well as other factors to consider when selecting the right product.


Like many ant killers, those specific to carpenter ants come in two basic types: baits and kill-on-contact insecticides. True to its name, the latter type of insecticide kills ants within seconds of contact. Kill-on-contact insecticides come in sprays and powders. 

These products kill ants almost immediately. Many leave a residue that will kill or repel other ants that scurry through the substance days later. Although kill-on-contact products eliminate the immediate threat, they aren’t effective at destroying the colony unless sprayed directly onto an anthill. 

A dry powder such as diatomaceous earth kills ants by infiltrating the cracks in the insects’ exoskeletons and dehydrating them, a process that takes up to a day. 

Insecticide gels, which typically come in syringe-style applicators, allow the user to apply small doses into cracks where ant activity is observed. Gels typically take several days to kill ants. This delayed action allows time for infected ants to return to the nest and infect the entire colony. Although these baits don’t offer the instant gratification that sprays do, they have better long-term results by eliminating entire ant colonies.

Active Ingredients

Ant killers use a variety of active ingredients. Borax is a particularly popular pesticide; the substance is deadly to ants but presents a low level of toxicity to humans, making it suitable for indoor ant baits. Hydramethylnon is another common active ingredient that’s lethal to ants. Other active ingredients used in ant killer include indoxacarb, avermectin, lambda-cyhalothrin, and fipronil. While these ingredients are relatively safe for use around homes, they do present health hazards. More importantly, these chemicals can wreak havoc on the environment, especially if they find their way into aquatic environments. 

There are pesticide alternatives that pose less risk to people, pets, and the environment. There are products that use essential oils from such natural sources as mint, cedarwood, cinnamon, and orange peels. Diatomaceous earth, which consists of the fossilized remains of tiny aquatic organisms, is also an effective way to kill pests by dehydrating them. There are environmentally friendly repellents that keep bugs away and don’t harm helpful insects, such as honey bees and ladybugs. 

Application Methods

Ant killers come in several forms, each with a different application method and specific means of killing carpenter ants. Shoppers will want to consider whether they prefer ant-bait stations, granules, sprays, or dust based on the following characteristics:

  • Bait stations are enclosed plastic receptacles with small holes that allow ants to enter, collect a liquid or gel bait, and then leave. An ant bait can take several days to kill, giving ants time to return to the colony and infect the population. Bait stations typically have liquid or gel ingredients that stick to the ants that enter. 
  • Granules are sprinkled on the ground, where they dissolve and leave a residue that kills ants on contact. Granules will treat the soil for several months and, when sprinkled to create a barrier around the home, prevent pest infestations
  • Sprays consist of a thin, sticky liquid that can be applied directly onto ants to kill on contact or to cracks and crevices where ants enter the home. Sprays leave a residue that infects and kills any ants that cross over it. 
  • Dust ant killers typically use diatomaceous earth. When ants crawl through it, the dust penetrates their exoskeletons and dehydrates them from the inside out. 


Many of the active ingredients in ant killers pose no serious health risks to humans. However, consumers should still be careful when using any pesticides in or around the home. When using an ant killer, it’s essential to take precautions to limit and prevent exposure. Keep the following tips in mind for application:

  • Always wear protective gloves when handling an ant killer. 
  • Don’t place baits in areas that are accessible to children or curious pets who may come into contact with them. 
  • Sprays and dust can be absorbed into the skin, so don’t apply them in high-traffic areas. 
  • Avoid treating areas where food is stored or prepared. 
  • When applying an ant spray, wear eye protection and direct the spray away from the eyes or any exposed skin.


Carpenter ant killers are effective at more than eliminating and controlling ant infestations. These multifunctional products can also take out a broad range of other common pests, including roaches, fleas, crickets, termites, and other insects. Most manufacturers list the types of insects the pesticide treats on the product container.

Additional Features

Many ant baits have additional features that make them suitable for use in different environments. Ant killers with syringe applicators facilitate targeted applications in areas such as the small cracks and gaps between baseboard molding that ants can infiltrate. This allows the user to treat the affected area without overspray, minimizing exposure to humans and pets. 

Bait stakes have a time-release poison that will not only take out existing colonies but also prevent ants from arriving and establishing new ones. Outdoor bait stations have waterproof housing to prevent rain from coming into contact with the poison, thereby ruining the bait station. 

Tips for Keeping Carpenter Ants Away Naturally

Although there are plenty of products that use chemicals to take out carpenter ants, there are also ways to keep carpenter ants at bay without using any pesticide at all. Carpenter ants are attracted to wet, rotting, or damp wood. Those who maintain their homes well and who repair damage as soon as it’s spotted are less likely to deal with carpenter ants. 

Carpenter ants also like heavily wooded areas, so keep brush and tree limbs away from the home’s exterior. Likewise, make sure mulch and soil do not come into contact with the wood parts of the home. Cracks and crevices around the home’s foundation can serve as an entryway for carpenter ants. Sealing these gaps will make it harder for carpenter ants to find a way in.

  • Repair leaks and water damage immediately.
  • Keep wood shavings, brush, and tree limbs off of the home.
  • Don’t allow landscaping to come into contact with wood parts of the house.
  • Seal cracks and crevices around the home’s foundation.


If you still have concerns about carpenter ant killers, read on for answers to some of the most commonly asked questions about these insects and products.

Q. Why do I suddenly have carpenter ants? 

Most carpenter ant infestations will occur when there is an active nest outside the home and the ants have found a crack or crevice in the foundation or wall. To keep any from getting in, always ensure that cracks and crevices are filled or use carpenter ant traps or killers. 

Q. What repels carpenter ants?

Carpenter ants use pheromones to create trails that other ants follow. You can disrupt this system of communication with essential oils that are effective yet safe for the environment. These include clove, lemongrass, peppermint, orange, and lemon oils, which confuse carpenter ants and prevent them from following the trail. 

Q. Does homeowners insurance cover carpenter ant damage? 

Damage caused by termites or carpenter ants is considered a maintenance issue that the homeowner is responsible for preventing. As such, it is not covered by most standard insurance policies. 

Q. What time of year are carpenter ants most active? 

Carpenter ants are most active from the spring to the early fall, usually operating between the months of March and October. However, a typical parent colony will reproduce in the spring, which is when homeowners will want to be on the lookout for signs of carpenter ants in the house

Q. Do carpenter ants go away on their own?

Once they’ve established a nest in damp wood, carpenter ants will not move away on their own. The nest will continue to grow and expand unless it’s treated, which can result in serious damage to the home and other structures. 

Q. How do you treat a carpenter ant infestation?

There are several options for treating a carpenter ant infestation. Granules for outdoor use are an excellent way to eliminate colonies in the yard or create a barrier around the house. Liquid baits designed for indoor use are a good way to eliminate colonies by infecting worker ants who deliver the poison back to the nest. 

Q. Will regular ant bait kill carpenter ants?

Although some ant bait can kill carpenter ants, check packing information to know exactly which species the product targets before making a purchase. 


Tony Carrick Avatar

Tony Carrick

Contributing Writer

Tony Carrick is a freelance writer who has contributed to since 2020. He writes how-to articles and product reviews in the areas of lawn and garden, home maintenance, home improvement, auto maintenance, housewares, and technology.