Oddly enough, known as the man’s best friends, dogs are notorious for their aggressive behavior and conflicts occurring between them and humans as well as other animals. No matter how strong the attacking dog is, this four-legged warrior perfectly knows that it is aggression, not strength, that decides the outcome of the battle.

What You Will Learn from This Guide:

As Dwight D. Eisenhower, the thirty-fourth President of the USA, put it: “What counts is not necessarily the size of the dog in the fight; it’s the size of the fight in the dog.” Indeed, dogs often manage to win a fight without physical contact.

By threatening barking, growling, and showing teeth they attempt to defeat the enemy before blood is spilled. In other words, to frighten off. And this is what we should learn from dogs and apply against them when the situation is becoming a powder keg. In military terms, this strategy has been embodied in the idea of nuclear deterrence: show off your combat capabilities in order to avoid a deadly confrontation with adversaries.

Now, what do we have in our arsenal? All sorts of sonic devices and dog repellent sprays. Rest assured, this is more than enough. Use these tools to imitate the behavior of wild animals by dispersing irritating substances or producing startling sounds.

Scientists say, yes, they are. According to researchers, a combination of visual and auditory devices is particularly effective on dogs. In this article, we have thoroughly examined the issue and set out our findings below.

However, prior to resorting to scare technics, get one thing straight: if a dog is getting aggressive, try to grasp why?

Samuel Siskind, a security expert, told Gadget Reviews about some basics of de-escalating aggressive dogs:

“Sudden fast movements (including running) can be perceived as aggression by a dog and trigger an angry response. Eye contact is also a trigger for dogs as it indicates an intent to confront. Stopping those actions will in many cases calm the dog down,” he said.

Why do they bark? The dog may be guarding its territory or defending the puppies. Sometimes, these animals turn aggressive with the noble aim of keeping peace between different groups of dogs. Perhaps, if you manage to grasp their motivation, no “weapon” will be required, all you will have to do is to remove the source of the immediate conflict.

Alright, you have come to a store or visited it online. You see a multitude of dog repellents and are wondering which one to choose. In order to get to the bottom of this, let’s look at the main features of repellents to understand what makes the product effective.

Dog repellents based on the power of sound may be loosely grouped into two categories: devices emitting loud sounds that stun dogs and ultrasonic repellents that affect their nervous system.

As for the loud sounds, nobody doubts that they produce the effect. Who would not be scared of the noise comparable to the clatter at a steelmaking factory? This comparison is not just a metaphoric expression.

When choosing a horn or other sonic device, check how many decibels it produces. Regardless of the source of the sound, it is decibels that measure its intensity. But since figures alone do not tell us much, let’s have a look at some illustrative examples.

A typical sonic dog repellent produces from about 110 to 130 dB. Where do we hear such noises? So, an average motorcycle produces about 100 dB, live rock music and steel factory — 110 dB, siren of an emergency vehicle — 115 dB, thunder blast and chainsaw — 120 dB, crowd noise at a stadium — 130 dB, aircraft taking off — 140 dB. Noise levels of 80-90 dB may resultin hearing loss in case the exposure is durable. With the level of 125 dB, pain begins. Now, you know why the level of decibels is that important.

Let’s move on to our another weapon — ultrasonic repellent. Both types of devices make an aggressive dog surrender by means of creating the atmosphere of fear and confusion. The difference is that ultrasound is inaudible to people and is good as a more durable solution.

Ultrasonic waves create noises which are gradually becoming unbearable for those hearing them. Dogs do perceive ultrasound and, depending on species, are capable of hearing in the frequency range of up to 45 kHz. As a reference, anything above 20 kHz is called ultrasound. But the main reason for using ultrasonic repellents instead of loud sonic devices is that we, people, can protect our ears from the shrill of horns and whistles.

As you know, distance is something that matters much in face-to-face confrontations. The closer your enemy is, the fewer chances you have of winning the fight… given the size of the enemy’s teeth.

Sonic dog repellents allow for scaring the animals away even though the distance is large. Put it otherwise, sound waves are your long-range missile while liquids and powders are the short-range ones requiring a close contact with the enemy.

Another disadvantage of sprays being used instead of frightening devices is that in many situations dogs have a natural ally in the form of the wind. If the weather is windy, nobody knows where the stuff from the spray canister will get. It may be you who will eventually suffer in this conflict. And finally, applying a repellent spray may not be a good idea if the matter concerns training your pet. Many sprays contain pepper as an active ingredient causing irritation and other undesirable health implications.

Sprays can come very cheap because they may be not only purchased from a shop but also homemade. Dog repellent sprays vary depending on whether they target the sense of taste, odor or touch. What should you decide on?

Well, if you have come across a stray dog, you will hardly wait until the beast tastes its prey. That is why you should opt for a pepper spray if you need protection during hiking, camping, and other outdoor activity.

The most popular ones are pepper sprays causing irritation and affecting the skin, eyes, and throat. Why are they that potent? The trick is in capsaicinoids which naturally makes pepper bitter. Every dog deterrent spray has its own outreach indicated by the producer. Be sure to read this information to know how close the animal can approach you so that you can safely discharge such dog repellent spray and hit the target.

Dog Chewing Deterrent. And yet, conflicts with stray dogs is not the only reason for using sprays. You might have a pet to train, first of all, not to chew the furniture in the house or valuable plants in the garden. For this purpose, choose repellent sprays based on vinegar and citronella oil. These dog chewing deterrents are pretty safe for people, their pets, and vegetation.

The stronger smell is produced by ammonia, a substance contained in the urine of foxes, coyotes, and other predators. The idea is that your pet will associate the smell of ammonia with the presence of a predator and stay away from the treated site. A very powerful but also a toxic solution.

But, what’s wrong with odor repellents? Just imagine that all your furniture, your skin smell repulsively. Besides, the smell will be accumulated when applied indoors. What would people think? That’s why you should better decide in favor of taste repellents when it comes to keeping your pets away from certain sites inside and outside the house.

Dogs, as you can guess, hate anything bitter. But there is something you need to know: you will have to be harsh with your beloved pets. Yeah, sad but true… Once the dog has tasted the bitter stuff, you will have to remove the water for half an hour so that the poor animal fully feels the taste of the chewing deterrent.

And not only that, taste sprays have other drawbacks as well. Some dogs may ignore the bitter taste because of their individual preferences while others, on the contrary, may be harmed if the substance has set off an allergic reaction.

A special case is a motion-activated sprinkler. It does not actually falls into any of the above-mentioned categories but is very effective in keeping dogs, both stray and pets, away from the garden. This deterrent creates a “water shield” protecting the plants, shrubs, and flower beds due to its smart technology allowing to detect any motion. Once the animal gets within the range of its sensor, the motion-activated sprinkler will send a sudden spurt of water towards the moving creature. Most of the time, that works. You can also check this best automatic dog doors review.




Effectiveness (1-10)

Sonic Repellent

Startles the dog immediately; can frighten the animal at a large distance; easy to use; doesn’t contain toxic chemicals.

Affects hearing both of people and dogs, especially if the exposure is long-lasting.


Ultrasonic Repellent

Inaudible to people; dogs are known to perceive ultrasound up to 45 kHz.

Ultrasound effectiveness as a repellent is still in question. A short-term solution.


Taste Aversion Repellent

Taste aversion sprays are the most recommended for keeping dogs out of the garden and preventing gnawing the furniture. They do not have the foul smell. 

Useless in preventing attacks of aggressive dogs. It may cause allergic reactions. The effectiveness hinges on individual preferences of the dog.


Odor Aversion Repellent

Can be used both to repel aggressive dogs and to keep your pets away from the garden. 

Weather conditions such as wind or rain influence its effectiveness. Some smells are repulsive to people as well. Evaporates quickly enough in the open air.


Motion-Activated Sprinkler

Does not require your participation. Physical contact with a sudden jet of water will surely frighten the dog off.

Responds to any motion, therefore, excessive water consumption is possible.


10 Best Dog Repellents

Having troubles with training your pets? Are you scared of aggressive street dogs? Below you will find a review of dog deterrent devices and sprays for both cases!

Startle attacking dogs with loud horns or school the pet with a sophisticated whistle. Choose ultrasonic devices to avoid a potential harm to the animals but keep in mind that they have different area coverage — from 15 to 50 feet. They can be portable or more powerful with loudspeakers and bark sensors.

To prevent dogs from entering prohibited areas on your property, install a sprinkler that is activated once its sensors detect anything moving and sprays the target with water.

Use a pepper spray to keep an aggressive dog away and a milder option, like a dog chewing deterrent based on bitter extracts, to discourage your pets from undesirable chewing.

1. HALT | Best Dog Repellant Pepper Spray 

HALT Dog Repellent Spray: photo

This spicy stuff is based on capsaicinoids which are pepper extracts and it works well on aggressive dogs. It should be sprayed directly in the face of the attacking animal. You are unlikely to harm the charging animal but rather will cause irritation for a while. 

The dog will be frightened and confused, which will allow you to gain time and walk away. Repeat the application to convince the attacker that you are not kidding. One canister of Halt deterrent spray covers an area of about 10 feet, quite a good result for a spray.

But you unlikely spray it on your beloved pet. Another weak point is that this stuff has to be inhaled and sprayed near the eyes to produce the result. In other words, the deterrent spray works on contact and cannot be applied as a preventive measure. Its rating is high: “I have used the Halt spray twice. Both times the dogs stopped pursuing me as I was running and turned the other direction. I haven't tried a standard pepper spray but I can testify that Halt does work,” a customer said.

Spray HALT:  Check the current price

2. Ortz Dog Whistle

An awesome sauce for dog training! It can be adjusted to different frequencies depending on the command — to sit, stop barking or else. Why is it that important to have an option of adjustable frequencies? The thing is that all dogs react to different sounds in a different way, some breeds are sensitive to one range while others are more prone to perceive another.

Ortz Dog Deterrent Whistle: photo

Just blow a blast and your dog will get the message while the training itself will turn into a sheer amusement. Has your dog run far from you so that you have to shout commands? Forget about it, just take the whistle and blow it. Your pet will understand you even from a large distance.

Since this is a lightweight and easy-to-use item, you may carry the whistle whenever you want without worrying about losing it thanks to the strap that comes with the product. A special cover protecting the device from dust and other particles is also included.

The whistle has gained almost 1,500 reviews. “This product is a blessing. It was easy to adjust the frequency to my pet. The whistle got my pet's attention and stop his inappropriate behavior(s) almost instantly,” a user wrote.

Ortz Whistle: Check the current price


Well, to frighten aggressive dogs you definitely need something more powerful and startling. Something like a deterrent horn. This hardcore stuff is said to repel dogs and other animals, making the device a top choice for hikers, camper, and joggers.

It produces about 120 dB of sound, which is quite impressive and is as loud as the noise of a thunder blast. The horn has a plain design and is easy to use — when holding it upright, press down on its top and … Whoops! You are a Lord of Thunder!


The DOG HORN stops most dogs in their tracks!
Break up and stop continuous barking with one short blast.


Dog Repellent Horn can sound either as the horn or the whistle. As customers say, both modes are extremely loud. And yet, do not use it in vain because the number of sound bursts is limited to over one hundred. Now, let’s move to the product’s dimensions. This deterrent is compact — 5.5 x 2.5 x 1 inches in size — and lightweight — just 1.76 ounces. So feel free to take it with you whenever you go outdoors.

star Excerpts from buyers’ reviews star

«I purchased this together with Halt, to shield my 3 lap dogs when we are out on area walks. Some individuals believe it is OKAY just to let their pet roam the area, and I stress over a dog assault. This horn is LOUD. If it is gusty and you have a spray defense, the spray would possibly end up in your own eyes. This is the initial point I use if an odd canine is approaching. So far it has actually been all I need. Stops the aggressiveness and no person gets hurt ... a win-win! ... Below it is a year later and this product simply conserved my canines' lives. It's a breezy day and also I had my 3 dogs out for a stroll. The breezy day part made pepper spray pointless. 2 big off leash german guards approached us with teeth prevented. I whipped the canine horn out of my pocket and also provided it a good blast, as well as they backed off. 10 seconds went by and they began approaching once more. I blew up the horn 4 even more times and also they went running the various other method. This might have been a completely various result. This horn is a life saver».

An obvious drawback is the absence of any fastener to attach the horn to the backpack or belt. It is crucial to draw the dog repellent quickly and sometimes every minute counts, while you may not be that fast if the thing in the bag.

“We go to the park and there are some aggressive dogs. The sound stops the escalation of a possible fight. It also makes me feel more confident that I don't have to physically get involved breaking up 2 dogs,” a customer said.

Horn: Check the current price

4. Sound Defense K9 Warning Device

A much pricier and fancy stuff to repel strange dogs and other wild animals. Sound Defense emits a very loud sound covering an area of up to 25 feet, which is crucial as you will not have to come close to a dangerous animal to frighten it off. The dog repellent shows an immediate result regardless of weather conditions.

Compared with the horn, this product has a clear advantage of a pocket clip being included. It also has the bicycle attachment allowing riders to keep the device on their bike. That is why the device is easy to carry, and most importantly, can be quickly drawn in the hour of danger.

It is larger and heavier, with 9 x 6 x 3 inches in size and 7 ounces of weight. And that is when its additional accessory, a holster, comes in handy. The drawback is that the seller has not indicated the number of decibels produced by the repeller, therefore, it is hard to evaluate how loud it is.

Sound Defense Dog Repellent: photo

According to some users, the device doesn’t work on all dogs, and if an animal is committed to aggression, the repellent will not do much good. Also, the seller warns that the product may not work on passive dogs as it is not intended for training.

K9 Sound Defense:  Check the current price

5. Hoont Electronic Handheld Dog Repellent

The idea is that an ultrasonic repellent emits a high-frequency sound irritating and confusing the charging dog. Compared to the sonic devices mentioned above, ultrasonic ones are more humane, don’t harm the animals and are inaudible to people. With these properties, however, they appear to be less powerful and giving a controversial result. Still, such repellents are in demand as well and below you will find the most popular ones.
Handheld Ultrasonic Dog Repellents: photo

Hoont is said to be capable of stopping charging dogs as far as 50 feet away — the longest distance of protection in our review. It is small and portable, just 4 x 2.5 inches in size, and easily fits into the pocket. People often come across strange dogs after dark, and that is when its built-in LED flashlight providing a minimum illumination comes very helpful. One buyer has noted that he has got mixed results. While two dogs in the yard quieted down immediately, a pit bull and lab on the street were not stopped by this dog repellent and kept on barking.

Hoont: Check the current price

Dazer II has more customer reviews, over 2,000, but has the similar rating on — 3.2 out of 5 stars. The producer says that the latest ultrasonic technology is applied in the device. Meanwhile, the reported coverage area is less that that of Hoont, amounting to 20 feet of protection

One of its benefits is a belt clip that comes with the product. “I find this very useful for deterring aggressive dogs outside. They usually change their focus, try to figure out what's going on, what changed, what will happen next. This confusion breaks the pattern of a dog's attack,” one user explained the mode of operation of this repellent.

Dazer II:  Check the current price

Although both Hoont and Dazer ultrasonic repellents are intended not only for repelling aggressive dogs but assist in training pets, it is worth highlighting First Alert dog repellent designed specifically to school a pet dog. The range of its impact is just 15 feet but the device is said to work on all breeds. When pushing a button, it is recommended to simultaneously use a verbal command, saying “no” or “off”, which will be helpful in training. “I put mine in the kangaroo pocket of a hooded sweatshirt, where it is hidden from view. A barking dog often is both stressed and not thinking,” a user shared his experience.

First Alert:  Check the current price

6. ELenest Outdoor Ultrasonic Dog Barking Deterrent for Yard

Has your backyard been attacked by barking dogs? Perhaps, your own pet does not obey you and creates too much noise? If yes, then this outdoor repellent is likely to solve your problem. The device has three built-in bark sensors with four sensitivity settings and one XL ultrasonic loudspeaker. You may tune it so that the device responds to a certain barking level.

Since it is waterproof, feel free to use it outdoors. Apart from hanging the device on a tree or pole, you may place ELenest on any flat surface or take with you on camping trips. Although this ultrasonic repellent is larger than the portable ones, it is easy to carry due to moderate dimensions — 8.2 x 5.6 x 5 inches. Its coverage area is claimed to be up to 50 feet and barking is detected at such distance as well.

Outdoor Ultrasonic Dog Barking Deterrent: photo

And yet, with over 4,000 customer reviews, the product has low rating. Actually, there are more critical than positive reviews. “This worked great for a week or two and now it's largely ineffective. I was so impressed with the first-week performance I bought a second one. In my case I was trying to prevent fence fighting between my dog and the 2 neighbor dogs,” a customer wrote. In fact, when it comes to the effectiveness of ultrasonic repellent, keep in mind that they always give a short-term result. You need to constantly change its position and frequency to keep on frightening unwanted intruders.

ELenest:  Check the current price

7. Orbit 62100 Yard Enforcer Motion-Activated Sprinkler

This is a hardcore stuff for garden and backyard protection, which works on various animals including dogs. Its operational principle is simple: a sensor detects the movement and initiates the repellent sending jets of water towards the target.

The technology is smart allowing to switch modes depending on whether it is day or night. This is important for avoiding excessive water and energy consumption, making the device energy-efficient. Also, it can be used just for irrigating the lawn. Orbit Sprinkler runs on four AA batteries. Since this dog repellent will be kept outdoors, its heavy-duty construction is a significant benefit.

Orbit Dog Deterrent Sprinkler: photo

Based on customers’ feedback, we can conclude that the device works on dogs well. Some users believe that much depends on a specific dog that may like water sprayed on them or not. Still, the spray comes out in a blast, which will hardly please the dog. “It works for me on dogs. The combination of water and noise seems to do the job. I no longer have to rake my mulch every morning. Follow the setup instructions carefully,” a customer said.

Orbit Sprinkler: Check the current price

8. PREDATORGUARD Solar Powered Predator Deterrent Light

PREDATORGUARD Solar Powered: photo

This is yet another frightening device from an American company, Predator Guard, dedicated to protecting farmers and gardeners alike from wild animal predation.

This device emits a powerful flash of light via twin red LED lights that animals think are the eyes of the predators. Researchers from the Denver Wildlife Research Center confirmed the effectiveness of a frightening light in reducing the attacks of coyotes on domestic livestock. In turn, the scientists from Cornell University suggested using such devices against street dogs.

The important part here might be to determine the correct mounting height for the device to be more effective. If you’re dealing with small animals, 12 inches might be a good height to start, for dogs, choose to mount the device 24 inches off the ground, for deer - 4 ft, and for owls - 8 ft.

As for the technical features of the device: It’s solar powered and will automatically charge itself on at night and off in daylight; the intermittent alternating flashlight ensures the animals won’t get used it.

The product is priced affordably and has received a lot of positive feedback, although mainly related to successful scaring off coyotes, but it’s reasonable to say that it should work on dogs just as well.

PREDATORGUARD: Check the current price

9. The Company of Animals Pet Corrector Dog Barking Deterrent

Press the button and the canister will hiss like a poisonous reptile. This simulation seems to really scare dogs since these animals have either encountered reptiles or have an inherited memory about the danger these creatures pose. Judging from customers’ feedback, this sound works on dogs.

The main benefit of Pet Corrector is that it produces a soft effect on the animals without harming their hearing as it may be the case with loud horns. Therefore, this repellent is recommended for schooling dogs. On the other hand, this advantage can easily be turned into a disadvantage if the matter concerns preventing attacks of street dogs. This type of sound may be too mild to startle the aggressor.
Pet Corrector Dog Barking Deterrent: photo

“I used it because we have 3 dogs who would get very excited (happy excited)when someone would come to our door. They would bark and jump etc. Now they sit back and are very calm,” one user said.

Pet Corrector: Check the current price

10. Grannick's Bitter Apple | Dog Chewing Deterrent

This dog chewing deterrent based on bitter extracts and alcohol. The spray is intended for discouraging dogs from chewing and gnawing the furniture, shoes or hair. When used on the furniture, including leather items, the stuff neither damages nor discolors it. Nor does it stains any fabric.

Grannick's dog chewing deterrent is safe so that it can be applied to the animal’s fur if you need to prevent it from licking the wounds, for example. What you should grasp is that the solution does not give an instant effect. Be persistent to let your dog realize that the thing it used to lick will never be that tasty anymore. To stop chewing, spray once a day throughout a week. It may take more time, just do not stop halfway. 

Dog Chewing Deterrent: photo

“It works well on plastics, we use it to keep our puppy from chewing his pee pads and the tray. The one thing you need to keep in mind with the spray is that it wears off so you need to reapply pretty frequently”, - a customer wrote.

Grannick's Bitter Apple: Check the current price

Rocco & Roxie

Rocco & Roxie No Chew Extreme Bitter Spray: photo

Rocco & Roxie is a popular American brand that makes an array of bestselling pet products that’s been trusted by consumers for many years. The No Chew spray from R&R that we feature here specifically aims at discouraging unwanted chewing. The product has 0.5% of tea tree oil (which is completely safe for dogs when used in such a low quantity) that has both antifungal and antiseptic properties and can be applied on a dog directly to discourage her from scratching herself or to protect her against flees.

Beside tea tree oil, the product contains purified water, emulsifier, and bitter agents (which the manufacturer claims are twice as bitter as its counterparts). It also doesn’t contain harmful chemicals and alcohol, which becomes ineffective after it evaporates. The products, considering it’s all natural and organic, can be safely applied to furniture, drapes, electrical cords, shoes, and directly on a dog’s fur or skin.

Unfortunately, though, the product has received a lot of mixed feedback, with a lot of consumers saying that their dogs indeed loved it and continued to lick and chew whatever they were chewing before even more vigorously and enthusiastically! Others, however, said it worked on their pets! So, see, it’s a hit and miss, and might not work for your pooch!

Rocco & Roxie: Check the current price

Deterrent Mat | High Tech Pet Sofa Scram

Dog & Cat Repellent Mat: photo

This HIgh Tech Pet Sofa Mat has become a bestseller in a very short time and is still gaining consumer love and appreciation! This mat is a “surprise” thing that works well both on dogs and cats. As soon as the pet touches the mat, it will emit a startling 95-decibel beep which immediately scares the frightened pet away. It’s completely safe, so there’s nothing to worry about. It’s battery operated (not included); can be used on chairs, sofas, beds, etc; and works pretty efficiently for pets over 5 lbs.

Consumers, as mentioned above, are overwhelmingly impressed by the performance of the product, saying it worked like a charm, trained pets very well, and was worth every penny! Besides, the price, indeed, doesn’t bite, so go for it and see for yourself!

High Tech Pet Sofa: Check the current price

Comparative Chart: Best Dog Repellents

Take these safety rules seriously, okay? Primarily, this concerns dog repellent sprays based on peppers since they can really be very hazardous. This hot stuff may occasionally contact your eyes and skin or you may inhale it.

The result depends on the level of concentration and how long you have been exposed to the pepper spray. In this case, you get burning and tearing eyes, redness of the skin, you may cough, sneeze and suffer difficulty of respiration. These symptoms may progress to more severe and permanent ones.

Then, what should be done to avoid these risks?

  • Practice in your backyard before applying the pepper spray in an emergency. Having encountered an aggressive dog, you may panic or be confused, which is not a good mood for starting to learn how to handle a new device.
  • You should be able to draw the spray easily. When going hiking, place the canister in a secure spot or fix it properly so that it does not accidentally fall out. The ideal solution is getting an appropriate holster to hold the spray, whereas keeping it in a backpack makes it useless. Remember, if the dog deterrent spray is not released in time, you are likely to lose the battle.
  • Do not simply hold the canister in front of you. If an aggressive dog is close to you, take a step back to create a distance.
  • Take into account the wind direction.
  • Aim the spray above the animal’s head, so the stuff will cover most of it.
  • Do not use the entire content of the dog deterrent spray at once. It will be more effective to produce a number of continuous bursts of spray. Particularly, repeated application is needed when the dog keeps on approaching.

When you use any taste repellent to train the pet dog to do or not to do something, take some precautions as well. In order to avoid possible harm to the animal, first, apply it to a cloth and let the dog taste it. Watch the reaction of your pets. If no severe symptoms are observed, apply the repellent spray to the objects you want to protect. In general, when it comes to liquid repellents, always read the label directions. Keep in mind that they all have different levels of toxicity and should be handled accordingly.

Read also: 6 Best Bark Collars | Train Your Dog to Stop Barking with a Variety of Effective Devices.