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Why Does My Dog’s Breath Smell Metallic? 8 Vet Reviewed Reasons & What to Do


Jun 7, 2023
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close up of a dog's mouth showing teeth and gums
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There’s nothing pleasant about the way a dog’s breath smells. No matter how many dental chews you give and how much brushing you do, your dog’s breath is probably always going to stink a little bit. It’s totally normal for your dog’s mouth to smell like, well, dog breath. However, changes in the way your dog’s breath smells can indicate a variety of things.

If you’ve noticed a metallic scent on your dog’s breath, here are some of the things that may cause it. Some of these causes are extremely serious, so make sure to get your dog to the vet if their breath starts smelling metallic.


The 8 Reasons Why Your Dog’s Breath Smells Metallic

1. Dental Disease

Many dog breeds are prone to dental disease, especially dogs with short snouts and crowded teeth, like French Bulldogs and Pugs, and dogs with small mouths, like Yorkies. Regardless of their breed, though, your dog can develop dental disease at some point in their life.

Dogs don’t brush their teeth two or three times every day like people do, and they tend to eat yuckier things than humans, so your dog is at a higher risk for dental disease than you might be.

Dental disease can develop at any age, but it is more common in older dogs. When a dog has dental disease, irritation of the gums is likely present. Oftentimes, there will be bleeding of the gums, although it may be mild and not noticeable. This can lead to a metallic smell in the mouth due to iron, but the effects of dental disease in general can lead to metallic breath in dogs.

vet checking dog teeth
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2.  Anal Glands

Dogs have two small glands located right inside their rectum. These glands are modified scent glands, so think of them as similar to the “stink” glands that skunks and ferrets have. Typically, a dog’s anal glands are emptied when they poop, but some dogs may struggle to naturally express their anal glands. This can be caused by multiple factors, including body weight, diet, anatomy, the presence of tumors, disease, and genetics.

Dogs that have full anal glands will likely begin to lick their behind in an attempt to ease the irritation. This often results in small amounts of anal gland discharge getting into the mouth, which can result in a metallic smell on the breath. Anal gland smell is usually associated with a distinctly fishy smell, but it often has a metallic twinge to it.

If you think your dog is having trouble with their anal glands, your vet will be able to check the glands and manually express them if needed.

3.  Kidney Disease

Kidney disease is an extremely serious condition that will eventually lead to kidney failure for your dog. Even with treatment, kidney disease will progress, eventually leading to complete failure of the kidneys. A metallic smell on your dog’s breath could likely be an indicator that they are experiencing kidney disease.

This metallic smell is caused by a buildup of waste products in the body due to the kidneys’ inability to filter these waste products out. In healthy kidneys, waste products are excreted through urine, but with kidney disease, the kidneys simply can’t keep up with the demand, leading to a backup. The metallic smell associated with kidney disease is likely to also have a slightly ammonia-like odor to it.

Sick mastiff dog sitting on table in a vet clinic
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4.  Diabetes

When a dog has diabetes, their body is not able to produce enough insulin naturally to keep blood sugar levels where they should be. This is why diabetic dogs receive insulin as part of their daily disease management. In dogs that aren’t receiving enough insulin or that haven’t been diagnosed with diabetes yet and aren’t receiving any insulin, the body loses its ability to break down consumed glucose into a functional product.

In order to get the functional glucose the body needs, the body will start to digest its own fat stores, resulting in ketosis. Ketosis will eventually lead to ketoacidosis, which is a deadly condition that should be treated as an emergency. When the body enters ketosis or ketoacidosis, the breath will take on an unusual smell. This smell is usually described as “sickly sweet,” but it can also have a metallic smell to it.

5.  Oral Tumors

Oral tumors in dogs can be difficult to spot. Most of us aren’t overly familiar with the inner parts of their dog’s mouth, and oral tumors can pop up anywhere in the mouth, even in hard-to-spot places. Oral tumors can be sneaky and may get a chance to develop significantly before being noticed.

The presence of an oral tumor is often first announced by excessively bad breath. Sometimes, this bad breath will smell metallic due to the body’s reactions to the presence of the tumor. Tumors in the mouth can be difficult to treat if they are allowed to get a stronghold in the mouth, so any new lumps and bumps in your dog’s mouth should be examined by a vet as soon as possible.

vet checking dog teeth
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6.  Coprophagia or Pica

Coprophagia is a fancy term that has a very simple meaning: eating poop. Some dogs just love to eat poop, whether it’s their own poop, the cat’s poop in the litter box, or the goose poop down at the local park. No matter what kind of poop your dog seems to fancy, eating poop will absolutely lead to excessively stinky breath. Pica on the other hand refers to the act of eating inedible objects like paper, wood, shoes, etc.

Most often, this bad breath will simply smell like whatever they have eaten from paper to poop. But, depending on what the animal has been eating, their health status, and other factors, their poop can have many types of smells. A dog having metallic breath after consuming poop isn’t at all unusual.

7.  Blood

The smell of blood is notably metallic, often being described as smelling like pennies. There are a lot of reasons that your dog may end up with blood in their mouth, leading to a metallic smell. If they consume poop that has blood in it, it can cause metallic breath. If they have a bleeding oral tumor or bleeding gums due to dental disease, they may have metallic breath.

Whether the blood is coming from your dog’s mouth or came from an external source, blood can leave behind a strong metallic scent.

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8.  Internal Bleeding

Although blood was just mentioned, it’s necessary to differentiate between blood being in your dog’s mouth and your dog having internal bleeding. If your dog suddenly develops metallic breath and you can’t find a cause for it, a vet visit is in order. If your dog has internal bleeding, it can lead to metallic breath, but you won’t be able to find an external factor, like an oral tumor or gum irritation.

Internal bleeding can be extremely deadly and should always be treated as an emergency. Internal bleeding is usually accompanied by symptoms other than just metallic breath, like pale gums, black or bloody stools, bloody vomit, and abdominal swelling. If there is any chance at all that your dog has internal bleeding, they need to be emergently examined.


Preventing Bad Breath in Dogs

There’s likely nothing you can do to completely eliminate the unpleasant odors associated with your dog’s mouth, but you can work to reduce them. Regular home dental care can reduce bad breath, as well as give you an opportunity to thoroughly examine your dog’s teeth, gums, tongue, and mucus membranes.

The obvious ways to prevent bad breath in dogs are things like keeping them from licking their anal glands and to not let them eat poop. This is easier said than done with some dogs. If your dog is licking their anal glands a lot, it’s best to have them examined since anal glands can become infected or develop tumors. Some muzzles can be used to prevent coprophagia in dogs, but make sure to properly muzzle train your dog to maximize success with this method.

Becoming familiar with the way your dog’s mouth typically smells means you’ll be able to tell when something smells different. Noting changes in breath odor can help you catch problems with your dog early, allowing you to get them treatment for serious and life-threatening conditions.

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Although some of the causes of metallic breath in dogs are benign, some of them are deadly serious. If your dog develops metallic breath and you can’t find a cause for it, it’s time to visit the vet. If you suspect internal bleeding or ketoacidosis, an immediate vet visit is necessary.

It’s possible that you’ll take your dog to the vet and the vet will find an obvious and simple cause for the smell, or they may not find anything at all and send your dog home with a clean bill of health. Taking action and getting your dog to a vet as soon as unexplained metallic breath develops may seem extreme, but it can save your dog’s life.

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