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Boric Acid Kills Bed Bugs, But Only When They Eat It

bed bug - Cimex lectularius

As the bed bug (Cimex lectularius) has re-emerged as a common household pest in recent years, boric acid has been a common tool used by pest management professionals and homeowners alike to try to control it. But, a new study in the Journal of Economic Entomology shows that the route of contact makes a difference: Simple external exposure to boric acid (such as in a dust application) is minimally effective against bed bugs, but bed bugs that ingest boric acid die swiftly. (Photo credit: Whitney Cranshaw, Colorado State University,

By Andrew Porterfield

After years of apparent dormancy, the bed bug (Cimex lectularius), has made a comeback in Europe and the United States. While the insects do not transmit disease, they are a nuisance, infesting bedding and other furniture and leaving clear symptoms of biting. As scientists try to determine a reason for their resurgence, pest management professionals and members of the public have searched through a number of eradication methods, including chemical pesticides and other treatments, with varying (and often negligible) success.

Andrew Porterfield

One common treatment has been to use boric acid on bed bugs, as a dust, spray, bait, paste, gel, or liquid. Dust may be the most common boric acid treatment, but it’s efficacy is not known. Some pest control advisors and agricultural extension agencies have even recommended not using boric acid at all. To help determine the efficacy of boric acid on C. lectularius, a team from North Carolina State University led by entomology professor Coby Schal, Ph.D., examined two ways to deliver boric acid: contact with dust or by ingestion. They also compared results to boric acid treatments on common German cockroaches (Blatella germanica), which boric acid can kill by both routes.

In a study published in September in the Journal of Economic Entomology, Schal and his team report that boric acid can kill a significant number of bed bugs—but only if the chemical is ingested. Bed bugs that eat boric acid at concentrations greater than 2 percent die quickly, and concentrations as low as 0.5 percent caused 100 percent die-offs, although at a slower pace. However, external contact with high concentrations of boric acid dust did not have a significant effect on bed bugs. By comparison, boric acid effectively killed concentrations of German cockroaches, regardless of the route of contact.

The researchers conducted four experiments on the bed bugs and roaches.

  • The first experiment involved feeding boric acid to 10 adult male bed bugs, at concentrations between zero and 5 percent. The bed bugs were fed for seven days.
  • The second experiment involved exposing bed bugs to boric acid dust. Here, 118 starved and 120 fully fed bugs were placed in dishes containing boric acid dust, and mortality was measured for 14 days. In the second experiment, the researchers also looked at whether boric acid particle size had any effect on bed bug mortality, homogenizing some boric acid powders.
  • The third experiment involved exposing German cockroaches to boric acid dust. One group of roaches had glued mouthparts (to prevent ingestion), while the second group was free to feed.
  • The fourth experiment involved injecting boric acid directly into the bed bug’s body (specifically, the hemocoel) to determine toxicity of the chemical to bed bugs.

Bed bugs had no aversion to feeding on boric acid at concentrations up to two percent, though the number of fully engorged bugs dropped to 80 percent at 5 percent concentrations.

Simple exposure only to the dust showed a 33 percent mortality rate among bed bugs after 14 days of observation. Increasing concentrations tenfold only increased unfed male mortality by 10 percent, and there was no difference between fed and unfed bugs. Nor did reducing the size of boric acid particles have any effect on bed bug mortality. In fact, more than 85 percent of fed bugs survived external boric acid exposure.

Injecting bed bugs did cause high mortality rates (up to 95 percent at higher concentrations), indicating a toxicity of boric acid to bed bugs that the insect’s cuticle is effective at staving off.

Ingestion, by comparison, was easily induced in bed bugs and highly effective at killing the bugs. A single blood meal with 0.5 percent boric acid killed 80 percent of all bugs in seven days. Concentrations above 1 percent killed all bed bugs within four days.

By also testing B. germanica, which can be killed by boric acid ingestion or exposure, the researchers found some clues as to how boric acid may work on insects. “It appears that this otherwise insecticide-susceptible strain of bed bugs possesses mechanisms that prevent boric acid from compromising or penetrating the cuticular barrier,” the researchers write.

Exactly how boric acid does its job remains a mystery, which presents challenges in designing baits to attract and ultimately kill bed bugs. But boric acid is a preferable chemical candidate for use in bed bug baits, since it is soluble and stable in water, is not as toxic to mammals as other chemicals, is relatively low cost, and doesn’t appear to trigger resistance by insects.

As for the use of boric acid in dust applications, though, the study shows such efforts are likely to be minimally effective against bed bugs. The researchers note that boric acid dust is widely available to consumers and pest management professionals and is effective against other urban pests, hence its common use. But, for managing bed bugs, methods to induce ingestion of boric acid will need to be devised.

Andrew Porterfield is a writer, editor, and communications consultant for academic institutions, companies, and nonprofits in the life sciences. He writes frequently about agriculture issues for the Genetic Literacy Project. He is based in Camarillo, California. Follow him on Twitter at @AMPorterfield or visit his Facebook page.


  1. How would bed bugs even be able to feed on boric acid…??

    Being inorganic…insects of course cannot gain resistance to boric acid. And cockroaches chew and consume so I’ve observed decent control of roaches using boric acid and using boric acid raked into carpets is a death sentence for flea larvae. Even ants consuming boric acid baits can work to control ant colonies though I’ve personally have never gained acceptable colony control with Terro or any/all boric acid ants baits such as Niban.

    Boric acid for bed bugs….I am puzzled as to how bed bugs are able to consume the mineral…! The effect boric acid has on the digestive system of bed bugs I get as will any insect be affected by the consumption of the inorganic but consumption?

    Plain silica aerogel such as Cimexa…basically an inorganic though manufactured…has worked well against bed bugs and I’ve talked to techs that have experienced decent results as well using plain silica aerogel but we know of course silica aerogel works mechanically.

    As with any product available to consumers..overdose/improper usage occurs far too often. Boric acid affects mammals too if exposed to overuse.

    • Hi Curt. The researchers on this study address this question at the very end of their paper, which you can click through to read at But I’ll quote it briefly here: “A major challenge in developing effective bed bug interventions is to develop, validate, and implement a bed bug bait. Their piercing-sucking mouthparts make this task particularly challenging for hematophagous arthropods. … The research we report here was conducted with boric acid dissolved in rabbit blood. Phagostimulants in blood likely maximized blood intake and possibly obscured some deterrence at higher concentrations of boric acid. However, Romero and Schal (2014) showed that the addition of ATP to water could simulate bed bugs to ingest large amounts of water. Furthermore, heat itself strongly stimulates close-range attraction and feeding in bed bugs (DeVries et al. 2016), so the combination of ATP, heat, and boric acid could be important components of a bed bug baiting system.”

      • Its so complex to understand where did the early pesticides go? Time is of essence to try to get back these chemicals which were used to get rid of these critters.

  2. Boric Acid was used to effectively control cockroach species in the 1970’s having proved to be much more effective than insecticides.

    • It also appears that when sprinkling baking soda on beds and rugs or wherever bugs are works well too. I tried it and they died shortly after walking on the baking soda.

    For those who think that bed bugs belong to developing countries are wrong. Bed bugs are on the rebound in developed countries breeding fast like sent curses from nowhere. From long time to now, bed bugs are known to be controlled with pesticides. But the unfolded development of pesticide resistance has led to a need for alternative control methods because of their increased surging to infest fast unstopped.
    Bed bugs are the most annoying and the creepiest pest alive in a house. So, their extermination process will be done using some effective strategic approach. These are the deadly insects which are mostly hidden under the bed or inside the bed sheet or couch. Their food is our blood. Yes, they suck human blood and can stay alive for a few days. As they do not move often, so mostly they can be found during the night. If not treated within time, then their infestation can lead to serious health hazards. Professional approach to remove bedbugs from your house is the smartest approach as home remedies don’t show effective results. Dealing with these creepy pests can be very dangerous if not treated correctly. Their reappearance is very obvious if one doesn’t take necessary expertise help.
    What Causes a Bedbug Infestation? How Common Are Bedbugs?
    Bedbugs are found in temperate and tropical climates worldwide. The insects are most commonly found in living quarters where their host resides. Bedbugs generally hide in the seams and crevices of bed mattresses and box springs, bed frames, headboards, upholstery, old furniture, closets, and in spaces underneath baseboards or behind loose wallpaper. Clutter and disarray also provide additional hiding places for bedbugs. Bedbugs may be transported from one location to another via luggage, furniture, clothing, and used mattresses. Although they are often associated with unsanitary living conditions, bedbug infestations also occur in clean, well-maintained living quarters, including five-star hotels and resorts. Bedbug infestations have been increasingly reported in hotels, dormitories, homes, apartments, nursing homes, cruise ships, shelters, jails, and hospitals.

  4. After 5 nights suddenly one evening i found three itchy bites on my shoulder. On inspection i found a dead bed bug (it’s body dry and 2 pieces) in a corner of my hotel room. I immediately changed to another room one level lower. I am scared i might have a bed bug in my bag or suitcase. I read your tip about leaving your bags outside your house. But I live in a small apartment in a building complex so I don’t know where I should keep them. Can I put my entire bags in plastic bags and spray from top first and carefully open the bags inside the plastic bag so that the bugs can’t escape? I have used rubbing alcohol to spray and kill bed bugs in the past. What would you spray them with?

  5. Boric Acid was used to effectively control cockroach species in the 1970’s having proved to be much more effective than insecticides.

  6. Boric acid for killing bed bugs? That’s right, this white powder you might have in your kitchen pantry is a powerful tool to have on hand if you’re battling with the little blood suckers. However, there is a catch. You’ll want a way to give them an incentive to eat the boric acid since it won’t harm you at all.

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