Do dogs have the power to detect when their owners are ill?

Shadow the dog on a couch in a living room

Shadow, a dog that can sense diseases

Smiling Nancy Best with blond hair

Nancy Best has a dog named Mia


Mia sniffing her owner Nancy who lays on top of a couch in a living room

Mia sniffed out Nancy’s breast cancer

Dogs have been domesticated for thousands of years and many breeds are prized for their keen sense of smell. Whether finding someone who’s lost, tracking a fugitive, or sniffing out explosives, the strength and accuracy of a dog’s nose is legendary. Marty Becker D.V.M., co-author of “The Healing Power of Pets”, is an expert on the subject:

“If you were to take a gigantic football stadium that NFL teams play in and fill the entire stadium with yellow tennis balls, and had one white tennis ball, dogs can smell the one white tennis ball in that entire stadium.”

Using this powerful sense of smell, is it possible a dog can actually diagnose life-threatening illness? Several dog owners have found persuasive evidence that dogs can save lives in mysterious ways.

Darlene Werremeyer with headphones on

Darlene Werremeyer’s dog Shadow saved her life

Nancy Best of Garberville, California, seemed to have it all. She was the mother of three healthy children and owned a successful coffee shop called The Java Joint. In fact, business was going so well, that she had recently opened a second store. Despite Nancy’s hectic lifestyle, her yellow lab, Mia, was always near-by. Nancy had gotten Mia as a puppy:

“Mia was the first dog that ran up to me. At the time, I didn’t know if I wanted a boy or a girl. Until she came up to me and I fell in love with her instantly.”

Nancy’s mornings were spent running the coffee house. But at about 1:00 P.M. each afternoon, Nancy set aside time just for herself and Mia. Then one afternoon, out of the blue, Nancy noticed that Mia was acting strangely:

“She came up and started sniffing and licking at my breast. And because she was eight months pregnant, I thought maybe she was kind of wigging out, so I didn’t pay any attention to it. I just went and told her to lay down.”

Shadow walking down the street on a leash

Shadow could detect low blood sugar

But Mia was persistent. The following evening, as Nancy was struggling to fall asleep, Mia began tugging at Nancy’s bedcovers:

“She started biting my shirt away like a dog bites fleas, little tiny nibbles and was trying to pull my shirt away from my body. I was starting to get upset with her.”

Desperate for her much-needed sleep, Nancy banished Mia to the backyard. The following day, during Nancy’s afternoon break, Mia did the same thing. Nancy couldn’t believe it:

“Mia jumped up on my lap while I was sitting up and dove with her nose into my chest. And the force of the pressure of her nose made me rub it because it hurt. And, when I rubbed it is when I felt the lump. I had had a negative breast exam by a physician just four months prior. There was no cancer in my family. I was 39, not old enough for a routine mammogram. So I was thinking this couldn’t be cancer, but the lump felt very odd. It was quite large.

Medical tests found Nancy had a cancerous tumor in her breast. A lumpectomy confirmed the worst: she had a stage two invasive ductile carcinoma, a very aggressive form of breast cancer. Marty Becker found out about how she discovered the lump and started to do a little research:

“When I first heard about Nancy Best’s case, I talked to an oncologist at the Mayo Clinic about it. And one of the things that we surmised there was that there was a certain smell that was being secreted. The type of tumor that she had in her breast may have had a certain kind of an odor. You have to remember, this kind of breed of dog is actually used for hunting. They have a very sensitive nose.”

Nancy had a partial mastectomy. Months of chemotherapy and radiation therapy followed. Since 2000, Nancy has been cancer-free. She thanks her dog Mia for potentially saving her life:

“The doctor believes that had this cancer not been detected at this time, within six months it could have entered my lymph nodes and I would have died.”

If it’s possible for a dog to sniff out cancer, are there even more profound life-saving powers a pet can offer? Darlene Werremeyer of Spokane, Washington, thinks so. She believes her dog, Shadow, is a prime example:

“He was the best medicine that I could’ve ever taken. If it was in a pill form, he’d be a miracle drug.”

After Darlene was diagnosed with diabetes in 1991, she had a series of medical setbacks. While recovering from open-heart surgery, she suffered a stroke. For a while, she lost her ability to speak. After several years of therapy, Darlene recovered her speech but had a problem with stuttering. At a family reunion, the anxiety of being in a crowd made that stutter even worse. Darlene Werremeyer:

“I was so nervous. I couldn’t talk again. And this little schnauzer named Maggie came up to me and started licking my hand. I started petting her. She got in my lap. And I noticed as long as I petted her, I could talk so much easier. It was phenomenal.

So phenomenal that as soon as she returned home, Darlene had to tell her neurologist:

“He said ‘Yeah, I know about dogs. I know how they can help. There have been lots of studies done.’ So he wrote a written prescription for a dog.”

So on doctor’s orders, Darlene adopted a schnauzer of her own, which she named Shadow. The bond between Darlene and Shadow quickly grew and Darlene’s speech improved. Dr. Carol Wysham, MD, was Darlene’s physician:

“We don’t fully understand why dogs have such an effect on people. But in Darlene’s case, she felt very calmed by the dog. Perhaps paying attention to the animal, petting and the sensory effects of that, could be actually just putting her more into a meditative trance.”

Soon after adopting Shadow, Darlene learned what an extraordinary animal he really was.
One afternoon, Darlene laid down for a nap and quickly dozed off. But Shadow was alarmed by something and would not allow her to sleep:

“He started pawing at me. He wouldn’t leave me alone. I sat up and the room just spun.”

Uncertain why Shadow was upset, Darlene checked the glucose level of her blood; it was dangerously low. If a diabetic’s blood sugar level drops too far, it can trigger unconsciousness or even a coma. Dr. Wysham:

“Shadow has helped Darlene in many different ways. Not only in her safety as far as being able to detect the low blood sugar, but also in her general life. Darlene now is able to walk without a cane. She is able to function and do the things that she wants to do on a daily basis.”

Darlene Werremeyer and Nancy Best have no doubt that they are alive because of the mysterious powers of their dogs. Marty Becker is equally amazed by the abilities of man’s best friend:

“The ability of these dogs to detect a seizure or detect cancer is probably equal parts their incredible sense of smell, their incredible ability to read body language, and then, also, what I call not just a sixth sense, but a ‘sick sense’. That’s that ability to know when something’s just not quite right. And then, the ability to draw near to help them. We should not be so amazed that pets are able to do this; we should be amazed by the amount of things that we don’t yet know they’re able to do.”

Watch this case now on Amazon Prime in season twelve with Robert Stack and in season seven with Dennis Farina. Also available on YouTube with Dennis Farina. Various seasons available now on Hulu.


  1. Lesley

    I got this virus I had no idea I had and it lasted years. I was dx from 6 yrs -13 yrs with AML. I thought it was treated and never would return. It came back at age 37 as a AML with Auto Immune Disease. My 1 year old Black Schnauzer starting biting and acting weird with me prior to this happening to me. He would be more protective always jumping on me to reassure me he was there and always sniffing at me and my private areas and my licking excessively at my skin. He would bite me which lead to bruises coming all over my body. I decided to check it out so I went to the Dr and right away the blood work came back really bad and I had to go to a Hematologist/Oncologist and she told me that I had AML with AutoImmune Disease and that she has to act on this quick. He still is acting like this with me my dog and it hurts because I am in pain sometimes and I he is a pup and a bit rambunctious and I have to yell at him and I get so mad with him because he won’t stop nipping at me what can I do.


  2. Arthur Bernstein

    I’ve have several Yorkies since 1977. But two of them were very extraordinary. Romeo was self-trained. This was proven when I placed ten fries on the edge of a table and told him to take them off in the order they were put there. He did. Romeo died young (4 years old) from undiagnosed viral encephalitis. He was replaced by Paris, a silver Yorkie, in 2001. In April 2003 I was hospitalized with something I later found was POA, caused by mold spores. After six weeks (one week in a coma), I returned home with instructions from my doctor that I was not to stand up too fast without physical assistance. I foolishly rose from my bed too quickly. I started to black out with my head aimed at the TV. Paris, two years old and only five pounds, rushed forward, grabbed my pants and pulled me back onto the bed. At the time, I weighed 165 pounds…and yet Paris pulled me back and saved my life. We remained inseparable until his death in August 2014 of kidney failure. He was 3 months shy of his 14th birthday. To this day, I still miss having him near me. Today, I have a rescue dog…a Yorkie…who sees to it that I exercise and eat properly every day. I’m 63 with high blood pressure and possibly Type 2 diabetes. My dog sees to it that I take my medicine daily and eat correctly as well as exercise for an hour each day, whether I want to or not. She reminds me by constantly barking at me and running from me to the counter, back and forth, until I take my medicine. My little babies are all life-savers and I love every one of them.


  3. Amy Gourley

    I saw a story on Unsolved mysteries about a seizure dog who had helped a young lady with seizures after she was in a bad car accident.I have been looking for a seizure dog for a long time.I was wondering if you could help me.because they are very expensive and hard to you think the people who train these dogs in the prison program could help me get a dog?thank you please write me back at you Amy


  4. Martha Bennett

    in 2010 i started having strokes, and out of nowhere i developed type 2 diabetes and they found a hole in my heart, heart stopage and a pacemaker. well our daughter moved back home to help take care of me and she moved in with her blue nose pit/johnson bull dog mix. well this adorable dog Triue, knows when i am having a stroke, sugar issues and migraines. she will not leave my side and will walk right up next to me protecting me. or she will inform me if i need to call my dr. so i agree whole heartedly with this report


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