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How Long Do Cockroaches Live After Being Sprayed?

It’s not uncommon to see cockroaches scurrying around after they’ve been sprayed with poison. It’s also normal to see even more roaches than before.

So how long can cockroaches live after you’ve sprayed them with poison?

The active ingredients in most roach sprays attack the cockroach’s nervous system, which causes it to starve, rather than die quickly. A roach can live up to two, or sometimes even three weeks after being sprayed with poison, so don’t be surprised if you don’t see instant results. 

How Cockroach Spray Works

Photo of different brands of cockroach insecticides being sold in a store.

The first thing you need to understand about cockroach spray is that it isn’t a poison that works instantly. Instead, the active ingredients in this particular poison are classified as “neurotoxins”, which work slowly. 

Pyrethrins are the most common type of poison found in cockroach spray. These chemicals will build up in a roach’s body and cause their nerves to shut down.

Neurotoxins can cause cockroaches to experience muscle spasms and tremors, which can make them flip upside down onto their backs. Once they’re upside down, they will have a hard time turning back over because of how top-heavy their bodies are. 

In this position, the roaches will end up starving to death. And even if they can flip themselves back over, the toxins will eventually paralyze them. 

Once the spasms are over, the neurotoxins in roach spray can cause their nervous systems to stop working entirely. It would take quite a lot of poison to completely shut down their nervous system though, and isn’t likely to happen. 

The roaches will be unable to move to find the food or water needed to sustain themselves, which will cause them to starve or dehydrate to the point of death. 

At this point, you can go ahead and sweep up and dispose of the roaches’ bodies. While they may be able to survive massive injuries and other disasters, their nervous systems are another story. 

How Long Does Roach Spray Take To Kill Roaches?

Most cockroach sprays aren’t instant killers. Many rely on the roaches’ muscle spasms to flip them onto their backs which lead to starvation. 

This process can take up to a few weeks, and may not even be successful if the roaches are resistant to the poison, or they can flip themselves back over.

Poison sprays can also cause cockroaches to become disoriented. This is generally considered to be the reason why you may see even more cockroaches than normal after spraying poison. 

The chemicals in the spray attack the nervous system, causing spasms and disorienting the cockroaches, making them more likely to run out into the open. 

This is the ideal time to dispose of the roaches’ bodies from your home. You’re more likely to find them in plain sight. Even if they’re only paralyzed or stunned by the spray, this still makes capturing and removing them much easier. 

It can take over a month after spraying before you completely stop seeing cockroaches in your home, thanks to their quick breeding cycles. 

Any eggs that have been laid by the roaches before you spray will still be able to hatch. Thankfully, the juvenile roaches will likely also be poisoned and in turn, won’t be able to breed. 

Can Cockroaches Survive Roach Spray?

It’s entirely possible that a cockroach can survive being sprayed directly with an aerosol poison. These creatures are incredibly resilient and durable.

Cockroaches have the ability to close off their bodies’ airways. This means they may be able to prevent receiving a sufficient amount of poison into their organs needed to kill them. 

In this case, the roaches may still experience symptoms of ingesting neurotoxins, but they may  be able to process the poison and essentially walk it off. 

Keep in mind that spraying their shells isn’t going to be very effective. Cockroaches’ exoskeletons are strong and durable, and are also coated with a kind of oil that doesn’t let outside moisture permeate them. 

In order to ensure that poison gets inside the roaches’ bodies effectively, they have to either breathe it in or ingest it with food. 

Cockroaches are also ever-evolving creatures. Some populations of roaches have actually developed a resistance to household insecticides. 

Roaches can only develop these types of resistance in a single generation which can render certain poison mixtures completely ineffective. 

Things To Remember When Using Roach Spray

While they are generally effective at eliminating cockroaches, poison sprays can also have detrimental impacts on humans’ health as well. That’s why it’s so important to always follow all directions as indicated on the poison. 

Be sure to clean any areas around where spray has been used thoroughly, especially those off of which you might eat. If you use cockroach spray in your kitchen, make sure you rinse any spray residue off the counters before you start cooking or preparing food. 

Sometimes it’s best to leave the room or your home for a while after spraying. This will give the aerosol time to leave the air and reduce the amount of fumes you inhale. 

When used properly, cockroach spray is generally considered safe for humans. 

The effects of the poison on humans can vary, depending on the individual’s size, age, health, the amount ingested, and sensitivity to the active ingredients in the spray. 

The Best Solution To A Cockroach Infestation

The best way to get rid of cockroaches in the home is to combine multiple removal and elimination methods. 

Cockroach spray is almost always effective when it comes to killing roaches, but it can pose potential health hazards to the people using it if it isn’t handled properly. 

Always use spray in high-traffic areas, avoid breathing in the aerosol, and follow the directions on the can closely. 

Glue traps are also an inexpensive, safe, and commonly used form of pest control. 

The sticky traps work best when combined with bait. When a roach steps onto the trap, it becomes stuck, and will either starve to death, wriggle free, or can be disposed of while trapped.

Poison baits can also be incredibly effective without posing any health risks to pets or people in a home. 

Boric acid and baking soda are other frequently-used items used to poison roaches. Both are slow-acting, but they can expand or dissolve inside a roach’s gut, causing it to die. 

You can try mixing your poison of choice with sugar and a little bit of water, then leave it in an easy-to-reach spot around cockroach hotspots. 

Making your home uninviting for roaches can also cause them to leave, and possibly prevent more roaches from entering your home. 

Essential oils, like peppermint and lavender, are also known to repel roaches while freshening the air inside your home. 

Seal up any points of entry into your home (such as drain pipes, the cracks around doors and windows, or holes in the walls.) 

Make sure to fix anything that leads to standing water (such as leaky pipes, basement wall cracks, or inefficient sinks.) 

It’s also essential to clean your home meticulously, get rid of any food crumbs (human or pet food) on or around the floor, and always store food in airtight containers made of thick plastic or glass. 

Finally, remove clutter around your home that could give roaches a place to hide. Old stacks of boxes, clothes on the floor, and storage areas are all common hotspots. 

If you find that you aren’t making a dent in your roach problem, it’s time to call in a professional exterminator. 

An exterminator will be able to estimate the size of your infestation, eliminate the roaches, and identify the root causes of the infestation, which you can hopefully fix in the near future.  


Cockroaches can live up to two or three weeks after being sprayed with poison, depending on which mixture of ingredients is in your chosen cockroach spray.

Rather than killing roaches instantly, most sprays on the market intend to paralyze the roaches which eventually causes them to starve to death. You may still see a few roaches up to a month after using cockroach spray around your home.