Why Does My Dog Have A Sour Smell?

How often do you try and wash the sour smell away? ¹

Dogs aren’t supposed to smell like a bunch of roses, but they aren’t supposed to stink up the house, either.

Every pet parent is accustomed to his dog’s normal smell, but when that changes all of a sudden it’s not only unpleasant, but also a cause for concern.

Why does my dog have a sour smell?

There may be a simple explanation, like the dog rolling in some dirty patch outside and a quick bath can easily solve this problem.

However, the sour milk coming off your dog might be the sign of a serious health issue so you should look for other symptoms, too.

In most cases, a trip to the vet will take care of the underlying cause and your dog’s presence will stop being so hard on your nostrils. 

In this article, we’ll have a look at the most common conditions that might make your dog smell sour.

Urinary tract infection

Urinary tract infections (UTI) are more common in spayed female dogs, but male dogs can get them, too. 

A dog gets an UTI  when the bacteria that colonizes the skin and gastrointestinal (GI) tract get  into the urinary tract. Most UTIs in dogs are caused by bacteria (especially E.Coli), but a fungal infection is also possible. It won’t be just the nether parts of the dog that give off a bad wiff, but also the mouth as most canines love to lick their genitals, even when they don’t have a problem. If the UTI is accompanied by a burning sensation when the dog pees, you can expect him to try to soothe the pain by licking himself even more, hence the bad breath. 

If you suspect your dog’s sour smell might be caused by an UTI, here are the symptoms you should watch out for:

  • Bloody and/or cloudy urine
  • Straining or whimpering when peeing
  • Accidents in the house
  • Asking to be let outside more frequently
  • Fever

If you notice any of these signs, you should take your dog to the vet as soon as possible. Left untreated, a urinary tract infection can lead to kidney failure. The good news is that a course of antibiotics will deal with the infection in a few days.

Yeast Infection

A dog can develop a yeast infection anywhere on the body, but most often it will appear on the paws, in the ears or between the skin folds. A yeast infection can cause a sour smell, although many pet owners are intrigued their dog gives off an odd sickly sweet smell.

Yeasts are spore-like forms of fungi that normally live on your dog’s body without causing any problem or bad smell. It is only when they start reproducing at a very fast rate that they cause issues. This can happen for a variety of reasons, including the dog taking some medication that reduces the good bacteria that keep yeasts populations in check. Yeast infections are more common in pets with a compromised immune system. Also they are more likely to occur in breeds that have many skin folds, such as Daschunds, Boxers, Chihuahuas, Poodles, Basset hounds, West Highland white terriers and some Sheepdogs. This is because yeasts thrive in moist environments like skin folds.

The main symptoms of a yeast infection include:

  • Redness or itching on their skin or inside the ears
  • Changes in skin texture (patches of skin may become leathery or thick)
  • Flaky, crusty-looking skin
  • Head shaking or tilting, when the ears are affected
  • Excessive scratching or rubbing against object to relieve itchiness
  • Hair loss
  • Swelling, warmth and tenderness in the affected areas
  • Drooling if the infection is in the mouth

How are yeast infections treated

The vet might run some tests to diagnose a yeast infection and recommend treatment. In most cases, your dog will need some topical antifungal creams, wipes, sprays, and medicated shampoos. In severe cases, the vet might prescribe oral antifungal medication.

There are also natural remedies you can try. One of the best options is cleaning the affected area with an apple cider vinegar solution. Do not apply undiluted ACV. Prepare a solution with one part ACV and three parts water. Soak a clean piece of cloth in the solution and gently wipe the affected area. This will help reduce yeast populations and provide a bit of relief to the unbearable itch. Do not use this solution inside the ears, or anywhere near the dog’s eyes or genitals. 

Frequent baths, preferably with an antifungal shampoo, will also soothe the itchiness while also reducing the presence of yeasts. 

Your dog could also use fatty acid supplements and it would be wise to reduce the carbs in his diet. Yeasts thrive on sugar, so try to reduce carbs such as potatoes, wheat, corn, or high-fructose corn syrup.

Anal glands problems

The anal glands are two small sacs located on the left and right of your dog’s anus. They produce an oily secretion with a very distinct smell. Every time the dog defecates the anal glands are expressed, marking the territory with your pet’s signature smell. If your dog has a problem with the anal glands, what you’ll notice is more than a sour smell, In most cases, the anal glands secretions give off a revolting, fishy smell that’s hard to mistake for anything else. 

If your dog has troubles expressing his anal glands, these may become impacted or an abscess may develop. Your dog’s rear may become swollen or discolored. He will also be in pain, which he might try to relieve by dragging his butt on the floor. And, yes, this will stink up your carpets, too. 

You should take the dog to the vet as soon as possible as an abscess can be very painful and it might lead to sepsis. An infection, no matter how unpleasant, can easily be cured with some antibiotics, but you will have to try to prevent such problems from reappearing in the future. 

Here is what you can do to help your dog express his glands normally every time he does a Number 2, so he won’t carry the stink back inside the house:

  • Increase the amount of fiber in your dog’s diet
  • Keep an eye on his stool to make sure it is well-formed, as soft stools don’t put enough pressure on the glands to empty them completely
  • Exercise your dog regularly 
  • Keep an eye on his weight.
  • Provide him with plenty of fresh, clean water.

Why does my senior dog smell sour?

Besides the problems mentioned above, elderly dogs can suffer from a variety of age-related issues, which might make them smell odd.

Dental problems

Many senior dogs suffer from dental disease, or periodontal disease. If your senior dog has gingivitis, rotting teeth or some other type of oral infection, his breath will stink. You will have to take greater care of his oral hygiene and the vet might recommend medications to treat any infection.

Kidney disease

This is also common in elederly pets. If your dog has developed a problem with his kidneys, these won’t be able to function properly anymore, leading to toxins buildup in the body. You need to see a vet as soon as possible as the infection could lead to kidney failure, which is fatal.


If your senior dog smells oddly sweet, this is a sign he might have diabetes. The odor comes from the mouth and is caused by a process called ketosis. This happens because, although sugars build up in the dog’s bloodstream, the cells cannot use it to get energy, so they start burning fats. The odd smell should be the least of your concerns. Diabetes will slowly damage your dog’s organs, including his heart, kidneys, eyes and nervous system.

Look out for other symptoms, such as

  • Excessive thirst, as the body tries to remove excess sugar through increased urination.
  • Weight loss, as the dog’s digestive system cannot  efficiently convert nutrients from its food.
  • Increased appetite

In advanced stages, the dog will manifest loss of appetite and lack of energy. While the disease cannot be cured, the vet might recommend insulin injections. Dietary changes and exercise can also help keep the problem under control.


At some point, you can expect an old dog to become incontinent and frequent leakage might cause a distinct smell. It’s not the old age per se that causes incontinence, but rather age-related diseases, such as kidney disease, infections and tumors. The doctor may recommend treatment for the underlying condition, but the only thing you can do is put up with your pet’s incontinence. In severe cases, he might need nappies. And more frequent baths. 

Closing thoughts

When your dog starts giving off a sour smell, a simple bath might not be enough to solve the problem. You can try that, of course, but if the problem persist you should consider the possibility he might have a health issue, like an urinary tract infection, a yeast infection or a problem with the anal glands. All these problems are easy to treat and your dog will stop smelling odd. However, if you have an elderly pet, the problem might be more serious and incurable. All you can do is manage the condition as best you can and put up with the smell. He still deserves your love, no matter what. 

Photo credits

¹ Photo by Bill Wren on Flickr

Sarah Pulsen

Hello, I have been in love with dogs since I was a little girl. I became even more infatuated with them when I was told by my Mum that I couldn't own one. Since I left home there has rarely been a time in my life when I have lived without a dog. My current dog is a Collie Terrier cross, called Ian.