What Everyone Ought to Know about Dogs Who Can Detect Cancer!

27 comments Dec 29, 2014by Denise Lessard

Can dogs really detect cancer ? The answer is YES.

Researchers have discovered that your four-legged friend cannot only smell cancer, but also be more accurate than the most advanced laboratories when trying to detect certain cancers.

When you think about detection dogs, you automatically associate them with illegal drugs and explosives. Right? Well now, you can add smelling cancer to your list!

Not only can a trained dog smell cancer, but your own dog at home can too. Many experiences testify that this has been done. We’ll get back to these experiences a little later in the article.

When you think about it, your dog has many advantages in warning you if he detects cancer. After all, if something goes wrong with you, something will go wrong for him too. He counts on you to bring him food and shelter, so he wants to make sure you always stay by his side.

The power of a dog’s nose

Dogs love to use their nose to smell food, people, animals and even wounds and cuts. Has your dog ever smelled a cut on you? Maybe you’ve personally experienced it. If you have a cut on your arm, your dog is able to smell it, even through your sleeve. They can smell the change and they will point it out to you.

A dog’s nose is already well-known to be an expert at smelling things. This is because they can smell in parts per trillion. This means less than a drop of blood in 20 gigantic sized swimming pools. That is 50,000 times more than a human. Isn’t that amazing?

Us humans love to use our eyes and we’re pretty good at it. When we enter a room, first thing we do is walk in and see the room. For dogs, they walk in a room and smell it. When you see a cat, they smell a cat; when you see a cut, they smell a cut. That is why dogs are so good at detecting drugs, explosives and missing people. Fortunately, now researchers, many other people and pet owners know they can detect cancer. Dogs are so good at it that they can detect it at a very early stage. Even at stage zero. Cancer has a smell. Even oncologists say that cancer has a smell that can be scented around stage 3 or 4 through a patient’s breath. If a human can smell it, it makes a lot of sense that a dog can do too, but at a much earlier stage.



How dogs pick up the scent

You know dogs have a powerful nose and can smell a large quantity of things, but how can they actually sniff cancer? Just how can they do it?

What’s impressive is that dogs can smell cancer from urine and breathe samples only.

A study was made with five dogs. Two portuguese water dogs and three labradors. They were trained to detect breast and lung cancer over a three-week period. The training consisted in smelling breathe samples only. 169 cancer patients and healthy volunteers were mixed into a group. 86 people out of 169 had cancer. They were asked to give breathe samples. The dogs each had to smell the samples individually.

When the dogs smelled cancer cells, they would lie or sit down next to the cancerous sample. The dogs got a reward when they detected cancerous scents. What were the results of the study? All dogs had accurately spotted out the cancers from stage zero to stage four in the mixed group.

Dogs who are trained to detect cancer are trained just like the dogs who learn to detect explosives and drugs. Trainers will give the dog a well-deserved reward after having targeted the right odour. The training might be similar, but the similarities stop here. While drugs and bombs can have one particular odour, cancer scent is a combination of thousands of organic particles that are unique to each human being. So before a dog can sense the smell of cancer “in general”, it takes a lot of samples of the common scent in order to become really good at it. In order to detect cancer, the dogs have to be trained to detect healthy breath as well. So, no need to say that this becomes what we can call very specific training.

What about your own dog? Can he really smell cancer even if he isn’t trained for it? Some people testify by their own experiences that yes, it has been done and it has saved their lives.



Some testimonials

Below you will read two short and touching experiences found in two online articles about two women who both got an early cancer detected by their dog. The following excerpts can be read thoroughly on theguardian.com and dailymail.co.uk.

About Emilie Clark and her dog Mia:

“One evening in November 2011, I was at my computer when Mia leapt on to my lap and nuzzled into the flesh at the top of my left breast. She closed her eyes and licked furiously. That frightened me because it's what she does when I have a bruise or cut.


I pushed her gently away but she fixed her eyes on mine and stared at me intently, as she does when she's alerting me to something. I was uneasy now. Mia seemed certain there was a problem with the area at the top of my breast. I couldn't distinguish anything – my breasts are naturally lumpy – so it was difficult. All evening Mia attempted to leap on to my lap and tend to the area of skin where she perceived a problem. The following morning, I visited my GP with a sense of dread. I asked for an ultrasound or a mammogram. I didn't start the consultation by telling him that my dog had alerted me to the possible abnormality – I was aware it might sound far-fetched, but when he was dismissive, saying it was unlikely I had breast cancer because I was only 24, I explained. (...)

None of the oncologists I met during my ordeal was sceptical about Mia's role in diagnosing my cancer – they had heard it before. There's a charity called Medical Detection Dogs that trains dogs to sniff out cancer, and its work is endorsed by Cancer Research UK. Scientists are researching how dogs possess this diagnostic ability so that humans can harness it. Fortunately, my cancer hadn't spread but it will be another 16 months of scans before doctors grant me the all clear. Meanwhile, I'm rebuilding my life. No matter what life serves up, the bond between Mia and me will always be incredibly strong.”

About Dr. Claire Guest and her dog Daisy:

“As Dr Guest, now 50, recalls: 'Daisy seemed to be pawing at my chest. She bumped against my body repeatedly - I pushed her away, but she nuzzled against me again, clearly upset.

'She pushed me so hard that it bruised me. Her behaviour was totally out of character - she was normally such a happy dog, who would never hesitate to race after the other dogs.'

'I felt the tender area where she'd pushed me, and over the next few days I detected the tiniest lump.'

A few days later she went to her GP who referred her to a consultant. He thought it was a cyst, but said he would do a mammogram to be sure. 'He was correct - the bump was a perfectly harmless cyst,' says Claire. 'But further in the breast tissue was a deep-seated cancer.' It was caught very early and she had a lumpectomy and some lymph nodes removed, as well as six months of radiotherapy.

'I was 46, and the specialist told me that by the time a lump had become noticeable, this cancer would already have spread and my prognosis could have been very different.

'Just as I was doubting the future of dogs being used to detect cancer, my own pet labrador saved my life.'”


How dogs help cancer researchers

Dogs just like Daisy, found in the above experience, helped detect not only her owner’s cancer, but over 500 other cases like this one after being trained to do so. Trained detection dogs not only help provide second line screening for cancers that are now still hard to diagnose reliably, but they also help in the development of electronic systems, that are also called “electronic noses or e-noses”, that will help in the detection of early cancers. All of this will be possible in an non-invasive way and at a very low-cost.

The electronic nose will be able to pick up molecules created by the cancer cells with considerable accuracy. More research needs to be done on the electronic nose, but once it’s ready, this technology will open a lot of doors to detecting many types of cancers.

Nowadays, cancer is a disease that is undoubtedly spreading and growing. You certainly want to do everything that you can to reduce your chances of getting cancer, or at least, be able to detect it at stage zero. You and I are blessed to have trained dogs who can really help make a difference and save many lives. Many organizations do some beautiful work to help advance resarch: dogsdetectcancer.org and medicaldetectiondogs.org are only two of them. Maybe one day we’ll be lucky enough to have a detection dog in every doctor’s office.

What do you think? Comment below.





About the author

Denise Lessard
Denise Lessard


Denyse Lessard is deemed as the “mother” of Zumalka, which was established more than ten years ago to provide easily accessible natural products for pet wellness worldwide.

Besides being a trained alternative medicine therapist, Denyse also has expertise in homeopathy, naturopathy and iridology, reflexology, as well as Chinese medicine. She is a long-standing member of the Professional Union of Homeopaths of Quebec, as well as the Association of Naturopaths and Naturotherapists of Quebec.

Denyse’s philosophy as regards pet wellness is not just about only dealing with disease and illness when they get in the picture, but keeping animals in ideal health each and every day.

Find out more about Denyse when you click HERE.


  • HOMEOANIMAL June 13, 2022 at 1:40 pm

    Hi Julie,
    I can understand how scary that can be for sure. It may be nothing, but you can always go for a routine checkup just to put your mind at ease.

  • julie a June 13, 2022 at 1:39 pm

    hi this has really worried me as i have a friend with a dog that constantly sniffs my stomach this is really worrying i can hardly go to my gp with no symptoms

  • Barbara June 10, 2021 at 4:57 pm

    Oh gosh!! I just realized why my cat, after 14 years of living with her, suddenly would sit on the floor at my feet and just stare at me. It was so weird and unlike her to do that. I told my family about her strange behavior. I thought she just wanted attention, which again was unlike her. I just now realize maybe she knew I had breast cancer!! This behavior started not long before I was diagnosed. I was treated successfully 2 years ago and am now going for my 2 year ultrasound. Could this be true!!! Boy, that would empty out all the shelters. Big Pharma may not like it, but I would love to see a dog in my doctor’s office. Did you know that some European countries are now using dog’s as covid screeners? The studies have proven they are almost faultless in detection. Maybe the world will start treating dogs more humanely. They truly are man’s best friend, and now may save our lives!

  • Melissa October 13, 2020 at 10:32 am

    I was diagnosed with stage III Non-Hodgkins a couple years ago. I went through treatment and have been in a “quiet phase”. For the last few weeks my dog is only content when I lay down on my bed. In the last few days he has literally started crying and whining at me until I go to bed, at all times of the day. I have my regular follow up appointment with my oncologist next week, I’m trying not to read too much into my dogs behavior… I guess I should share this with her. If my cancer is back, I’ll know that is what he has been trying to tell me. Dogs are amazing.

  • HOMEOANIMAL July 13, 2020 at 1:19 pm

    Hi Mary,

    Thank you for sharing your story with us. For sure our pets are very in-tune to us and our pains and emotions. So for sure in situations like this the best is not to take any chances and get a full check up to see if there are any serious health issues such as cancer.

    We hope it turns out to be nothing or nothing major for you!


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