Why Does Rubbing Alcohol Kill Roaches?

When a roach appears on my counter, I will be the first to admit that I don’t always pause to think about the best course of action; I grab what’s nearest and use it as a weapon to kill the pesky invader. On more than one occasion, that makeshift weapon turned out to be a spray bottle of alcohol. Interestingly enough, it has proven to be both the most effective and utterly useless attack method possible.

Alcohol is typically used as a cleaning product and, just like soapy water, can lead to a few dead roaches but may not stop a roach infestation. I have never had a pest control professional recommend alcohol as one of the many reliable remedies for roaches. However, anecdotal evidence suggests that common pests like American cockroaches and German cockroaches can be killed via direct contact with a stronger enough blast of isopropyl alcohol. Let’s explore how that is possible.

Does Rubbing Alcohol Kill Roaches?

Isopropyl alcohol may kill the odd roach or two that crawls into your house when the weather outside is bad but is unlikely to do anything against a cockroach infestation. Better remedies for roaches are white powder treatments like DE (diatomaceous earth), borax (boric acid), or bath salts (Epsom salts).

Like soapy water, the fumes of isopropyl alcohol can suffocate roaches if it is sprayed into their airways when they are trying to breathe. Since a roach can go several hours without adding new oxygen to its system, effectively killing roaches with alcohol can be tricky.

Rubbing Alcohol, 16 Fluid Ounce (Pack of 2)

Dropping a cockroach into an alcohol bath or using a very high (91%) percent alcohol can be one of many remedies for roaches that appeared suddenly and leave you with no other method of extermination other than squishing, which leads to more messes.

The most effective way to use alcohol against roaches is to cover the cockroaches with alcohol and then ignite them, but this can lead to a potential fire hazard and should only be done in an inescapable fireproof space like a bathtub or metal drum. If you can’t do this safely, then it is best to resort to other pesticides or a natural insecticide.

Roach Killing Mixtures

Sometimes pests in the house are a regular occurrence, if not a constant one. After a few days of being roach-free, maybe a few will stumble inside to escape rising water levels after rain or extreme cold and droughts. As roaches try to slip into our homes, certain everyday mixtures can help keep roaches away and also double as effective cleaning products.

Other than the discussed 71 or higher percent alcohol and water, some other common combinations include hydrogen peroxide and water, vinegar and water, dissolved salt and water, as well as boric acid and water. Below are the effects of these combinations on cockroaches.

Alcohol and Water  Stun and SuffocateCan prevent cockroaches from getting oxygen if constantly sprayed for hours
Hydrogen Peroxide and Water  Stun and BurnStops roaches and causes discomfort in roaches, direct sprays to the face may kill a roach if it ingests enough
Vinegar and WaterStun and KillAcidity burn of vinegar can kill roaches, but it has to be at 10% or higher concentration
Dissolved Salt and WaterRepel and KillEpsom salt is toxic to cockroaches and will kill them if ingested
Boric Acid and WaterKill and RepelIngested borax kills roaches, and once they know it is nearby, they will avoid the area
Dish Soap and WaterKills and RepelsSoap suffocates roaches and can have scents that repel other roaches nearby

Steps to Exterminating Roaches with Isopropyl Alcohol

Killing cockroaches with isopropyl alcohol is not as easy as using boric acid or other proven chemicals to stop pest insects. However, with the right technique, it is possible and can help you out of a jam. If a cockroach can escape, then it might be hard for you to sleep, thinking it could reemerge at any point.

While not the best method to stop roaches, using high concentrations of isopropyl alcohol against cockroaches can help with peace of mind. Below are the steps to stop a cockroach with rubbing alcohol.

Locate Roach

It can be hard to spot pests that like to move around under the cover of darkness. Often flipping on a switch to illuminate a room without any natural light will lead to any bugs scurrying out of sight. If you do happen to see a roach, you will want to act quickly, or it may be difficult to find and destroy it later. Once you see the roach, you must move immediately.

Grab Roach Spray

Mix a strong batch of alcohol of at least 70 percent into a spray bottle and keep it on hand in rooms where roaches enter. Bathrooms and kitchens are good places to have these bottles for sterilization and sanitation purposes anyway. If you have the spray in the room, grab it without taking your eye off the pest.

Check Surroundings

Make sure there are no open flames, people, or pets between you and the roach or in the potential spray line. Consider fans and open windows that could blow the alcohol out of the expected spray line. If there is an obvious easy escape path for the roach, make sure to spray from that side to avoid hitting the back of the roach, where it will have no effect.

Wait for Roach to Stop

A moving roach is hard to kill with alcohol. Unlike chemical pesticides that can kill on direct contact, alcohol can not. To kill the roach, you need to replace any oxygen with alcohol to suffocate it. The only way to do that is to spray it in the face hard, fast, and repeatedly. If you miss the first spray and the roach escape, you will have done nothing to deter this pest.

Spray the Roach

Spray the roach repeatedly in the face for maximum effect. A roach will run towards the nearest dark, tight hiding spot, so spraying along that line as the roach runs can lead to disorientation and cause it to stop. Once a roach is stationary and cannot find, a way out, you will have all the time you need to apply enough alcohol to kill it.

Eventually, the cockroach will fall to its death or flip over in the corner like all the other roach corpses.

Kill and Remove Cockroaches

It can take hours for a roach to die from suffocation. While this may be satisfying if you hate roaches and get a sadistic enjoyment from slowly killing them, but in most cases, it is a waste of time to finish them this way. Once a cockroach is immobilized from the alcohol, another method like smashing or simply scoping and flushing the roach can rid you of the problem hours sooner.

Why You Shouldn’t Use Rubbing Alcohol to Kill Roaches?

With a huge selection of products shown to effectively stop roach infestations without harming humans or pets in your household, there really is no reason to go out of your way to kill roaches with alcohol. Some types, like methanol, can be toxic to pets and humans and shouldn’t be used to remove pests inside. Other treatments can lead to excessive exposure to rubbing alcohol in the air and cause skin irritation and rashes.

Any type of alcohol common to homes will be highly flammable. You should never spray near open flames, a volatile heat source, or even an incense burner. While ignited, alcohol will burn off very quickly, if the flames are able to contact fabric or paper, a fire could start quickly.

Since this method is not effective against fast-moving roaches or a full-scale cockroach infestation, it really isn’t all that practical. Unless, of course, you like the idea of spraying a cockroach in the face for hours. Then rubbing alcohol will kill roaches.