Your Dog Has Bubbles or Foam on His Mouth – Should You Worry?


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When you think of a dog foaming at the mouth, probably the first thing that springs to mind is the movie “Cujo,” and the possibility of rabies. Certainly, foaming is one of the most visible symptoms of advanced rabies, but there can be any number of other reasons why your dog has bubbles around his mouth. So, I’ll talk about rabies in this post, but also about other causes, some serious, and others not so much.


There are many symptoms associated with rabies, and a dog having bubbles or foam at the mouth is just one.

There are two types of rabies – furious, and paralytic. A dog with furious rabies will be agitated, enraged, and may gag or choke. Ultimately, cardiac arrhythmias will develop, and the dog will become paralyzed and die.

Paralytic rabies usually manifests as apathy, depression, confusion and disorientation. The dog will also appear to be hallucinating. Then a period of hyperactivity will ensue, followed by stiffness at the back of the dog’s neck. Ultimately, the dog will become comatose and die from respiratory failure. This type of rabies is most commonly transmitted by bat bites.

A dog with rabies will also develop a high fever, which is the body’s natural immune response – its attempt to kill, or at least slow down, the virus.

As to the foaming, the reason for this is that the rabies virus is very good at ensuring its survival. One way that it does this is by creating an aversion to water (this is why rabies used to be known as “hydrophobia”). As the dog’s brain begins to swell and his mouth dries out, the salivary glands go into overtime in a futile effort to ease the dryness in the mouth, and foaming occurs.

Rabies is pretty rare these days, so why do we still think of it first and foremost when a dog has bubbles or foam on his mouth? Probably one reason is that the disease is so entrenched in our collective memories, having been documented in primitive artwork as far back as 4,000 years ago. Another reason is likely that until the early part of the 20th century, there were no reliable vaccinations, and little in the way of a cure. In fact, even today, rabies is very difficult to cure in dogs – that’s why we vaccinate.

Losing a dog to rabies is heartbreaking – the dog suffers horribly, and you also have to live with the guilt, knowing that a simple shot would have protected your best friend from this terrible death. In some areas, rabies vaccinations are mandated by law. Even if you’re not legally required to vaccinate, though, please do, especially if you live in an area (as I do) that’s populated by bats, raccoons, foxes, or skunks that can carry the virus.

See Everything You Need to Know About Rabies for more on this disease.


Rabies is easy to prevent, but epilepsy often isn’t. Sometimes, it can be the result of exposure to toxins, but in most cases, it’s simply genetic, and it can cause your dog to display bubbles or foam at the mouth, depending on the severity and length of the seizures. Other symptoms can include weakness, disorientation, confusion, difficulty walking and incontinence. A dog may also have bubbles or foam at the mouth, because he’s overheating. A “grand mal” seizure is pretty easy to identify, since the dog will lose all control of his limbs and almost invariably foam at the mouth. Other seizures may be less easily identified, so the general rule of thumb is, if you think anything is “off,” see your vet.

Epilepsy is a condition that should never be ignored – even one seizure is cause for a visit to the veterinarian. The longer the seizure, the greater the potential for brain damage. Epilepsy and other seizure disorders can be treated using medication.

Some breeds are at higher risk for epilepsy and other seizure disorders than others. They include (but are not limited to) Golden Retrievers, Labradors, Beagles and Vizlas. Generally speaking, seizure disorders will develop within the first three years of the dog’s life.

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Poisonous Toads

I know, you’re shaking your head at this one – I did too, when I was researching this post. If you’ve had your dog vaccinated against rabies, and you’re out for a walk in the woods, you probably don’t worry all that much about encountering infected animals – if you do, you’ll just keep your distance, and even if your dog does end up being bitten by a rabid fox, skunk, or other animal, you won’t have to worry, because he’s protected.

But what happens if you get home, you know that your dog is protected against rabies, but there he is, with bubbles or foam on his mouth? It couldn’t be rabies in any case, because the disease takes a while to get to that point. What could be going on?

He might have encountered a cane toad, or a Colorado River toad.

The good news is that this is pretty unlikely, since these types of toad aren’t all that common. The cane toad is usually found in southern Texas and Florida, while the Colorado River toad lives only between New Mexico and California. If you live in any of these areas, though, please be cautious.

Dogs that think these toads might make good chew toys, or who even lick one out of idle curiosity, can pick up secretions that cause irritation leading to the dog developing bubbles or foam in the mouth area. Usually, these toads are active at dawn and dusk, but that’s not to say that your dog might not encounter one during the day. Usually, they keep to themselves, but they also like to scavenge, so don’t leave dog food or human food remnants out where they might attract the nasty creatures.

If your dog does encounter a cane toad or a Colorado River toad, get him to the vet as quickly as possible.


An anxious dog may pant excessively, and this can also lead to the dog having bubbles or foam in the mouth area. Sometimes, this can be due to separation anxiety, a trip to the vet, or anything else that the dog finds unpleasant. This isn’t a huge health issue, but if your dog does seem to be salivating or foaming a bit much, make sure there’s plenty of clean, fresh water on hand so he doesn’t become dehydrated.

Excessive Exercise

Dogs love to run and play, and this can also cause dehydration. The more your dog pants, the more hydration he loses, and what remains can manifest as bubbles or foam. So, if you’re planning on a lot of physical activity with your dog, make sure to bring along some bottled water and a bowl.

Difficulty Swallowing

If your dog is having trouble swallowing, he may also foam at the mouth, and he might also experience breathing difficulties. Either of these conditions should be evaluated by a veterinarian as quickly as possible.

Oral Health Issues

If your dog’s oral health isn’t good, he may hyper-salivate because of stress. He might have an injury, an abscess, or even a tumor, and any of these conditions can cause a dog to have bubbles or foam in the area of his mouth. Again, this isn’t something that should be ignored – you need to take him to the vet.

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The Final Word

If your dog has bubbles or foam in or around his mouth, you don’t need to panic. If he’s up to date on his shots, it’s not rabies. The presence of froth in the mouth area can, though, indicate other conditions. Some are serious, so if you’re not sure what’s causing the problem, see your vet.