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Why Does My Dog Smell My Breath – 5 Key Reasons!

Most people do not enjoy waking up in the morning to their dog sniffing their face and around their mouth. Having your dog trying to smell your breath throughout the day is a widespread occurrence for most dog owners. Regardless, this leaves many dog owners wondering: why does my dog smell my breath? 

Dogs smell people’s breath to gather information about a person. By sniffing someone’s breath, a dog can determine what they had to eat that day, their hormone levels, and even if they have an illness.

In this article, we will be explaining all of the reasons why dogs smell people’s breath. We will also be answering some commonly asked questions about dogs sniffing their owner’s breath, along with some other things you should consider regarding this topic. In addition to this, we will be taking a closer look at which diseases dogs can detect by smelling a person’s breath. 

Reasons Dogs Smell Your Breath

There are five main reasons why dogs like to smell the breath of humans. Usually, dogs are just attempting to gather some information about you. Many dogs can be trained to detect and alert others of disease, medical condition, or the onset of a health problem in a person just by smelling their breath. 

In addition to this, sometimes dogs smell their owner’s breath because it smells good to them. This is especially common if you have just eaten a meal or if you have just woken up from a night’s sleep. Here are the five reasons dogs smell your breath. 

Your Dog Is Smelling Something You Ate 

Dogs have such a strong sense of smell that they can smell what you had for breakfast even at the end of the day. Therefore, dogs frequently smell their owners’ breath because they can smell that you had something good to eat.

This is usually the cause of your dog smelling your breath just after having a meal, mainly if you just ate something your dog loves, such as chicken or peanut butter. Many dogs do this, and it is nothing that an owner should be concerned about. 

You Have Morning Breath 

Dogs love particularly smelly scents, and our morning breath is no exception. For this reason, many dogs love smelling their owner’s breath when they wake up.

Although this behavior can become bothersome to many dog owners, this is an entirely normal occurrence for dogs. Luckily, this behavior can be stopped rather quickly and usually doesn’t continue after you brush your teeth. 

Your Dog Is Gathering Information 

Dogs can gather a lot of information by smelling the breath of a person or another dog.

In addition to learning what you ate that day, dogs can discover the smell of your hormones, the levels of various essential brain chemicals such as serotonin and dopamine, and even if you have a disease or health condition. As a result, many dogs smell their owners’ breath simply because they gather some information about them. 

Your Dog Is Greeting You 

Due to the fact that dogs can gather so much information about a person just by smelling their breath, many dogs will smell their owner’s breath when greeting them. This behavior stems from that of their wolf ancestors. 

Wolves have been known to smell the breath of other wolves to learn information about them. Usually, this information involves what food another wolf has eaten, but they can learn many other things about the members of their pack by smelling their breath. 

This is almost always the reason behind dogs smelling their owners’ breath when they are greeting them after their return home from work. When this happens, your dog is just trying to figure out what you have been up to when you were away. 

Dogs Can Smell Diseases On A Person’s Breath 

Dogs can smell many different types of diseases and health conditions on a person’s breath. As a result, many dog owners report that their dog acts strange when they get sick or have a new medical problem.

Some dogs have even been trained to detect specific diseases and health conditions from people’s breath, such as various types of cancer. 

In addition to this, many dog owners have reported that their dog began to act strangely in situations like their owner having low blood sugar, the onset of a migraine, and even the onset of a hormonal imbalance.

This was all just after smelling their owner’s breath. Not only could a dog detecting and alerting their owner of this prevent something like a migraine from ruining their owner’s day, but it could also save their life in certain situations.  

Is It Normal For Dogs To Smell Your Breath

Yes, it is normal for dogs to smell your breath. This behavior is instinctual to dogs, and it is one of the best ways to get information about a person or animal. Therefore, this is just a natural way for dogs to learn about their owner and what they usually smell like. 

Some dog owners even encourage their dogs to smell their breath because they can detect things like the early onset of a migraine or low blood sugar in people with diabetes.

This allows people with these conditions to take preventative medicine or do things like correct their blood sugar levels before a more serious problem occurs. 

Can Dogs Smell Illness On Your Breath

Dogs can reliably detect many different types of diseases, medical conditions, and health problems on a person’s breath.

Therefore, many scientists and dog trainers have trained dogs to alert their owners when they smell changes on their breath resulting from a disease or medical condition.

These diseases commonly include various types of cancers, but other health conditions can be detected by a dog’s nose as well. 

The following table lists the diseases and health conditions that a dog reliably detected by smelling a person’s breath.

Disease or ConditionDetection Accuracy Rate
Breast Cancer88%
Lung Cancer99%
Migraine Onset54%
Low Blood Sugar (Type I and Type II Diabetes)81%

It is important to note that the test regarding the accuracy rate of dogs being able to detract and warn their owner of the onset of a migraine was self-reported.

This means that scientists did not conduct this test; instead, people affected by migraines reported whether or not their dog detected the onset of a migraine before one occurred. Although this study is still significant, it may not be as accurate as some others on our list. 

How To Stop Dogs From Smelling Your Breath

Although a dog smelling its owner’s breath is not necessarily a problematic behavior to most dog owners, some may not want their dog trying to smell their breath.

Unfortunately, the only way to reliably stop a dog from smelling your breath is to stop rewarding it and prevent it from happening altogether. This is because smelling people’s breath is a self-rewarding behavior in dogs. 

You can stop rewarding your dog from smelling your breath by getting up and ignoring your dog for several minutes after he smells your breath. This way, your dog will begin to associate smelling your breath with fun stopping.

However, because this behavior is so self-rewarding to dogs, this training can take a very long time and requires consistency from everyone your dog encounters. 

Other Things To Consider

There are some other things that you should consider when it comes to dogs smelling your breath and dogs detecting things like illnesses, medical conditions, and other medical problems from their sense of smell.

These include whether or not letting your dog smell your breath is unsanitary and what other diseases dogs can detect by smelling other types of samples from people.

 In addition to this, considering the reasoning behind the differences in success rates and why we do not see disease sniffer dogs in most medical settings is also helpful to understand.

Here are some things you should consider about dogs sniffing your breath and detecting diseases in people. 

Is It Bad To Let My Dog Smell My Breath

Although it is unsanitary to have your dog stick his nose inside of your mouth, allowing your dog to sniff your breath from a distance is not a bad thing at all. As long as your dog is not uncomfortably close and is not trying to lick your mouth, allowing him to smell you and your breath is completely fine. It may even strengthen the bond with your dog. 

In addition to this, your dog could alert you that something is wrong if he smells your breath and begins to act strangely. Therefore, a dog could potentially alert their owner to take preventative medicine to correct a health problem or even, in some cases, save its life. 

Dogs Can Smell Disease From More Than Just Your Breath

We have already listed all of the diseases and medical conditions that a dog can smell on a human’s breath. However, dogs can also detect illnesses, medical conditions, and other medical problems by smelling other things.

The most commonly used samples used for dogs to detect diseases other than their breath are blood samples, urine samples, and sweat samples. 

For example, dogs can detect Ovarian cancer from a blood sample extremely accurately. 

In addition to this, dogs can also detect prostate and bladder cancer from urine samples. They can also detect other diseases and conditions from sweat samples, such as malaria and narcolepsy. 

The following table lists the diseases and health conditions reliably detected by a dog smelling the blood sample, urine sample, or sweat sample of a person. 

Disease or ConditionSample UsedDetection Accuracy Rate
Ovarian CancerBlood Sample97%
Prostate CancerUrine Sample71%
Bladder CancerUrine Sample41%
MalariaSweat Sample70%
NarcolepsySweat Sample11 out of 12 patients detected (roughly 92%)

It is important to note that the test conducted on dogs who can detect narcolepsy from a sweat sample was only conducted with two dogs and twelve patients, a very small sample size. However, the high accuracy rate still makes this statistic noteworthy.

Why Don’t We Use Dogs in Medical Settings

At this point, you may be wondering: why don’t we use dogs in medical settings if they can detect things like lung cancer so accurately? There are, unfortunately, a couple of reasons why you do not typically see disease sniffer dogs in places like medical clinics and hospitals. 

The first reason is that many of these studies derived our statistics from still need more testing to be used clinically.

For example, Dogs have only been tested on how they can detect narcolepsy once, and the number of people and dogs tested was reasonably small. Therefore, although this study is noteworthy, there is still insufficient evidence to use dogs to diagnose narcolepsy alone.

Another reason why dogs are not commonly used in the diagnosis process on a clinical level is that most doctors do not feel comfortable having a dog diagnose a disease, especially one as serious as cancer.

Instead of using dogs to detect diseases and health conditions, most doctors rely on other testing methods. Nevertheless, dogs’ ability to sniff out diseases like lung cancer off of a person’s breath shows some fantastic potential, and it has even saved some lives already.