Puppy Bad Breath: Causes, Teething and Poop Breath

Everyone talks about sweet puppy breath. Then one day your puppy yawns in your face and the smell hits like a wet sock. It's a common surprise, and it usually has an ordinary cause.

Puppies have their own set of reasons for stinky breath. Teething, retained baby teeth and a taste for things they shouldn't eat all play a part. This guide covers what's normal, what isn't and what to do. For adult dogs, see dog bad breath.

Why puppy breath changes

Very young puppies drink milk and have almost no bacteria on their teeth. Their breath is mild. Then the mouth changes fast.

Puppies get 28 baby teeth, which finish erupting at about 6 weeks, according to VCA. Around 12 weeks the adult teeth start pushing in, and the baby teeth fall out. By 6 months, most puppies have a full set of permanent teeth. Adult dogs have up to 42.

That's a lot of change in a small mouth. Gums are sore and inflamed. Tiny cracks open where teeth shift. Food hides in those gaps. Bacteria love it.

Think of a kid with a loose tooth who avoids brushing the sore spot. The same thing happens to your puppy, and the smell follows.

Quick guide: smell, cause and what to do

Teething: the most common reason

Teething starts around 3.5 to 4 months, when the baby incisors are replaced, and runs to about 6 or 7 months. Your puppy might drool, chew furniture, whine when eating and have blood-tinged spit. A small spot of blood on a chew toy is common.

Blood on the gums has a metallic smell, and bits of food and saliva add a sour note. The result is breath that smells off for a few weeks. It usually settles once the adult teeth are in.

Here's what helps:

• Offer chews made for puppies. They should be soft enough to dent with your thumbnail. VCA warns that hard bones and nylon toys can break both baby and adult teeth.
• Freeze a wet washcloth for your puppy to gnaw on.
• Brush gently once a day, even if it's only a few seconds.
• Check the mouth weekly. VCA suggests weekly mouth checks from puppyhood until about 7 to 8 months.

Chewing is normal and doesn't stop at 6 months. VCA says it eases around 18 months. Redirecting it matters more than stopping it.

Retained baby teeth

A retained (persistent) baby tooth is one that stays put after the adult tooth comes in. You can spot it when your puppy seems to have two teeth in one spot, often a double canine, a bit like a shark.

Small breeds and flat-faced breeds get it most. VCA lists Chihuahuas, Pugs, Bulldogs, Boston Terriers and Boxers. The upper canines are the most common ones. A Yorkie puppy with a "second set" of fangs at 6 months is a classic picture.

It matters for breath because food gets trapped between the two teeth and the gum. Tartar builds up quickly and the gum becomes inflamed. It can also push the adult tooth into the wrong position. When lower canines are affected, the adult tooth may grow toward the roof of the mouth and cause an injury.

VCA recommends removing retained teeth during the teething window, between about 3.5 and 7 months. Early removal usually lets the adult tooth move into place. It's often done at the same visit as spaying or neutering, so ask your vet to check during your puppy's vaccine visits.

Puppy breath that smells like poop

This one worries owners, and it's usually simple. Puppies eat stool.

Vets call it coprophagia. Puppies do it for several reasons. They explore with their mouths. They copy other dogs, including the mother. They may be bored. Sometimes a puppy eats stool after being scolded for an accident, because it hides the evidence.

The AKC lists stool-eating as a cause of bad breath in dogs. It also carries a health risk. Stool can contain worms and other parasites, and the habit passes them around.

What to do:

1. Pick up stool right away, indoors and in the yard.
2. Teach a firm "leave it" and reward your puppy for walking away.
3. Take your puppy out on a leash for toilet trips so you can interrupt.
4. Tell your vet. A stool sample and deworming schedule are routine for puppies anyway.
5. Don't punish accidents. It tends to make things worse.

If the smell is feces but your puppy hasn't been near any, think about the other end. Vomiting that smells of feces, a swollen belly, or a puppy that stops passing stool can mean a blockage. Puppies swallow socks, toy pieces and bits of rope. That's an emergency. Read about dog vomiting for more.

Chewing habits and what goes in the mouth

Puppies put everything in their mouths. Some of it sticks.

A stick wedged across the roof of the mouth, a thread of cloth fiber between the teeth or a splinter of bone can all cause a rotten smell within a day. Your puppy may paw at the face, drool or refuse food.

If you see something and it comes out easily, remove it. If not, call your vet. Don't use tweezers deep in the throat. If your puppy is gagging as well, see coughing and gagging.

Also watch what your puppy eats off the floor. Garbage, dead animals and cat litter all leave a smell. Some foods can be toxic too. For example, see whether chocolate is a risk if your puppy has been in the pantry.

Less common causes

Most puppy bad breath is mouth-related. But a few causes sit outside the mouth.

• Tummy upset. Puppies with a sour stomach or reflux can have sour breath.
• Infection. A swollen face or pus around a tooth points to an abscess. A cracked baby tooth can do this.
• Inherited conditions. Rarely, a puppy has a liver problem from birth. The signs are poor growth, vomiting, odd behavior and a foul smell. That's a vet visit.
• Kidney problems. Rarely, young dogs have kidney disease, which can bring an ammonia smell. See dog bad breath for the full smell guide.

Starting good dental habits

The best time to teach tooth brushing is right now. Puppies who get used to it early accept it for life.

1. Choose a dog toothpaste in a flavor your puppy likes. Never use human toothpaste.
2. Let your puppy lick a little off your finger for a few days.
3. Rub a finger over the gums and teeth for a few seconds.
4. Move to a soft finger brush or a small brush.
5. Aim for once a day. Keep it short and end with praise.

Merck notes that gum disease won't develop around clean teeth. That's an easy rule to remember. Dental disease is the leading cause of bad breath in adult dogs, and good habits now keep it away later.

When to see a vet

Book a visit if the smell is strong or rotten, lasts more than a couple of weeks, or comes with swollen gums, a retained baby tooth or trouble eating. Go the same day if your puppy is vomiting, lethargic, has a swollen face or won't eat or drink.

Mention bad breath at every vaccine visit. Your vet can check the bite and the timing of tooth loss in a minute. For more on dental care across a dog's life, visit the Dental and Bad Breath hub.