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September 19, 2018 5 min read

Dog Face


If you are a dog lover or owner, then nothing fills you with more dread than the idea that your best friend might have a serious illness or worse, cancer. Naturally, if there was any way of knowing, or asking your dog how they felt, you would jump at the opportunity.
But dogs are clever and will try to give us signs to let us know how they are feeling.
As an author, I have unfortunately lost a dog to cancer and had I had this knowledge at the time, it would have made me feel more in control and more at peace. This article will go over the twelve common signs of cancer in dogs that any observant owner must know.

To understand what types of common cancer there is in dogs, we suggest some background reading.


Collapsing or Lethargic Behaviour

Starting with the most obvious, if your dog collapses or falls unconscious you should seek urgent medical veterinarian help. Lethargic behaviour is subtler. This could mean that either your pup does not ‘feel’ like doing things that they would normally love, due to a lack of willpower or energy. This could be sleeping for long hours of the day, not showing interest at walk times or even not barking/greeting visitors at the door. If your dog collapses or is lethargic for a spell, then the next day seems completely fine, take them to the vet anyway as it might be a hidden problem. 


A mild sign that still deserves its placement on this list. If your dog coughs once or twice, then it’s unlikely unrelated to cancer (Many small dogs have some trouble breathing and coughing is completely normal) but if a dog coughs for large fits over a few days, then it could be a sign of lung cancer.

Look to see how your dog breathes after exercise. If they are unusually short of breath despite previously being able to exercise just fine, then maybe it is a sign that something is wrong.

Rapid unexplained weight loss / Appetite loss 

Because of the way that we feed dogs (the same amount in their bowl every day of the week, plus a few treats and titbits from the dining table) should make your dog have a very consistent weight. If your dog happens to suddenly start to lose weight or have the appearance of ‘struggling to hold onto weight’ then that is a call for concern. Whilst, not a sign of cancer straight away (The dog might be simply feeling ill, have parasites or does not like the new food available), combined with other items on this list it can be influential.




Oral afflictions 

Oral afflictions could be anything from ulcers to bleeding from the gums, to strange breath. Fortunately, as dog owners, we are well acquainted with our dog's mouths thanks to the frequent and loveable kisses we receive. We are well placed to notice if anything is amiss, such as an odd smell, change in gum colour and lumps/bumps. These could be signs of oral cancer/tumour and should be easily spottable (They are generally associated with areas of the gum suffering from blood loss). If you are unsure, invite your puppy for a few treats and examine them as they eat, looking for paleness or pale spots in their gums.

 If you are more comfortable, you should be able to lift the lip of the dog’s snout to see the gum line in detail.

Nose afflictions

A random blood nose is cause for alarm in humans and should be treated exactly the same in dogs. Particularly in older dogs this can be a sign of nose cancer and should be examined by a professional. In a younger dog, it might be a sign of a foreign object. At any rate, unless you physically saw your puppy hit something with their nose, then its always a cause for concern.

Bathroom habits 

Owners should always keep a watch out for any changes to a dog’s bathroom habits or if there is anything different about the way they remove waste. If what was previously solid is now always runny then that is a warning sign. Also look for blood in the stool as it would be a sign that something is bleeding internally. Look for spots of blood over a few days, as a slight bone or non-digestible object might have passed through, and whilst still bad, will disappear and heal in a few days.

This can also mean if a dog wants to go many times a day (begging at the door to be let out) or not at all, then there might be something wrong. 


Persistent discharge, such as fluid or pus, leaking from areas of the body is an alarming sign that something is wrong. Discharge from the nose is a sign of a tumour in the respiratory system, and from the eyes could be from an optic or a brain tumour. The key word here is persistent. There is likely nothing to worry about if your dog has some discharge that disappears after a few days (After all, even dogs get a runny nose when they have a cold).

Also look for multiple sessions of vomiting, as this can be a sign of stomach cancer. 


Cancer In Dogs



Seizures can be caused by a brain tumour putting pressure on other areas of the brain. This can take the form of uncontrollable spasms, such as biting, chewing, mouth foam, legs moving uncoordinatedly and vibrating. Look for bursts of activity not unlike when a cat is spooked.

If you do see this, it is critical that your dog goes straight to the vet right away.

Skin Changes 

One of the easiest ways to check for signs of cancer in your dog is to check their skin for any changes. As we love to hold, hug and stroke our puppies, it can be easy to notice any new changes in their skin. Be sure to feel under the skin for any new lumps, bumps or swelling, as these can be signs of new cancerous growth. Be sure to look out for sores that won’t heal and are discharging fluid.


Bloating is the opposite of weight loss commonly associated with most cancer signs in dogs and is when a dog can’t seem to stop putting weight on, despite a regular diet. Unfortunately, most of the time this is not fat, but actually the collecting of fluid around the body. This can also be seen if the dog suddenly starts to ask for more food or has a sudden strong appetite. Look to see if your dog is also lethargic which could be a sign that they are not receiving energy from their food.


Lastly, the one sign that we fear the most is that your dog is suffering from pain. If your dog is whining for no apparent reason (Your dog whingeing desire for affection compared to pain is very pronounced, and it will sound unlike anything you have heard before), heavy panting or crying out, then they may be in pain.

One simple way to check is to offer them a treat or a favourite toy and see if they stop crying. Additionally, by picking them up or giving them a pat might cause them to whimper, as you physically touch the sore spot.

No one wants to see their puppy in pain, and through the steps that we have outlined above, the observant owner can pick up on the signs of something serious. Be sure to take action and prevent a tragedy. 

Share this article with others who have dogs and you think should know the cancer signs.

Yunnan Baiyao Store
Yunnan Baiyao Store

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