Dogs That Changed the World
Medical Dogs

Medical Dogs

Dogs That Changed the World introduced Daisy and Tangle, dogs able to sniff out cancer cells, and Delta, a German Shepherd who can sense changes in the blood sugar levels of her young master. The talents of these special animals are matched by those of tens of thousands of remarkable canines — dogs trained to sense disease and seizures, to assist the physically and emotionally disabled, and to provide comfort, affection, and therapy to their human companions.

Medical Research

Daisy and Tangle were trained to detect the unique odor of bladder cancer cells in urine samples, but researchers have found that dogs can also nose out other forms of cancer. At the Sensory Research Institute at Florida State University in Tallahassee, scientists have trained dogs to detect the odor of skin melanomas and prostate cancer. In 2006, researchers at the Pine Street Foundation in Northern California reported that they had taught dogs to pinpoint patients with lung cancer (with 97 percent accuracy) and breast cancer (with 88 percent accuracy)-simply by sniffing their breath. The researchers are now training dogs to detect ovarian cancer.

Service Dogs

Dogs like Delta are trained to detect subtle changes in a diabetic patient’s body chemistry that occur when the levels of glucose in the blood drop too low or rise too high. Either can lead to seizures, convulsions, diabetic coma, and death. Other dogs have been trained to respond to heart attacks, and to recognize changes in the blood pressure of their owners.

Delta can sense changes in blood sugar   

Delta, a German Shepherd, can sense changes in the blood sugar levels of her young diabetic master.

Dogs known as seizure dogs (or seizure response dogs) have been trained or have learned to react when a person with epilepsy is having a seizure. These dogs might bark to notify others of the seizure, lie down next to the person to prevent them from harm, remove dangerous objects from the vicinity so the person is not harmed, or attempt to revive the person after the seizure ends if they lose consciousness. More remarkably, the companion dogs of epileptics may learn to sense an impending seizure in their owner before it happens. In a 1998 survey by researchers at the University of Florida, 10 percent of epileptic patients with companion dogs reported that their dogs seemed to know when they were going to have a seizure. Although experts aren’t sure exactly how dogs do this, it may be that they are detecting subtle changes in body chemistry or in the behavior of their owner. In some cases, these dogs have been trained to perform a particular activity — running in circles, for example-to notify their owner of what they have sensed.

The most widely used and well-known service dogs are those trained to provide assistance to blind or visually impaired people, acting as the eyes of their owner. There are also hearing dogs, trained to assist deaf people and to alert them to sounds such as smoke alarms, doorbells, and crying babies; mobility assist dogs, which pull wheelchairs and provide help to the physically impaired; and walker dogs, which help provide balance when walking to individuals suffering from movement disorders such as Parkinson’s disease and spasms. In addition, dogs have been trained to assist persons with psychiatric conditions such as bipolar disorder, post-traumatic stress disorder, autism, schizophrenia, and anxiety disorder. These dogs learn to recognize changes in their owner’s behavior or environment that indicate paranoia, panic attacks, hallucinations, or potentially harmful repetitive actions, for example, and may remind them to take medication.

Therapy Dogs

Therapy dogs provide comfort and affection and improve the general well-being of people in hospitals, nursing homes, mental institutions, retirement homes, schools, and even prisons. In addition to providing companionship, researchers are now finding that the dogs are legitimately therapeutic. For example, in a 2005 study by the American Heart Association of hospitalized heart failure patients, researchers found that a 12-minute visit with a therapy dog reduced blood pressure and levels of stress hormones, and eased anxiety. Therapy dogs have been shown to improve the focus and memory of patients with Alzheimer’s, encourage speech and simple physical activities among stroke victims and individuals with impaired mobility.

Many organizations now test and provide accreditation to therapy dogs. The dogs must meet rigorous standards of temperament and obedience; they have to be accepting toward friendly strangers, sit and stay on command, be able to walk through a crowd with wheelchairs, and not startle easily.

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  • Kenny Case

    I have a daschund that can sense pain in my body. I have a bad knee that when it hurts he licks it a lot. When it does not hurt, he ignores it. The same for other parts of my body. And he licks in in a way that makes it feel better (different ways at different times). Should I try to get the attention of a research team to breed him for future medical reasons.

  • T.R. Morris, ND

    Does your knee swell, warm, or redden appreciably when it is painful? Does the dog do this for anyone else? Try testing him if not. If you can, teach him to search for pain on yourself and others. As far as research teams go, I’m not sure if you’d best approaching a veternary nerologists or human rheumatologists. Probably both.

    As a physical medicine doctor, I have learned that I can run my hands over a person’s body and locate injured or inflamed regions, and pinpoint the source of pain with deeper touch. I have never known how exactly I do it. My guess was a subconscious sense of size, warmth, turgor, or electrochemical activity, but without research, it is impossible to know for sure.

  • Brandon Benjamin

    I just watched “Dogs that changed the World” and i think its amazing dogs dogs can sniff out cancer. I have heard of this before where a dog sniffed out a womans breast cancer and saved her life – w/o being trained.

    I have searched for information on this topic without success. My interest stems from having cancer now twice and at the age of 25 imagine it will happen again. I had Leukemia at the age of 11 then relapsed and had a Bone Marrow Transplant at 18. I would give anything to have a cancer detecting dog. What can i do?

  • Alyssa

    I love dogs and it`s so interesting that they can do that. I found out that there is something in dog saliva that can hurt your kidneys.

  • Pam Spitler

    Your program “Dogs that changed the World” just made “mans best friend” even a “better friend, thanks for the wonderful presentation.
    Pam and Danny Spitler along with their best friend Moorea. We are supportors of PBS.

  • Tiffany Carter

    I just watched Dogs that change the world,I have type 2 diabetes and was really intreaged by what I saw.I’m looking for a dog now. I live alone and after watching your program I want to find one that will alert me when my sugars are to high or to low.but I dont know where to look.could you please help me with my search?

  • Anirvan

    Does anyone know what kind of a dog is the one in the picture? The dark brown one with the gorgeous eyes?

  • louis Pisano

    my mother is very ill, had a tumor removed, seizure problems big concern, where do i find these dogs, please advise Thank you, a son in dire need

  • Krista

    About a year ago my dog started acting really funny twards my uncle, barking and growling, acting afraid and we couldnt figure out why. Well a month later we found out he had brain cancer. I believe our four legged friends have a better idea of whats happening in our bodies then we do.

  • Elizabeth

    I saw this show last year and have thought about it ever since. Today my school wants us to research what career we want. I desided that I would like to help people with medical peoblems with dogs. But I do not know what I can do to help. I would like adive in this career area. Thank you PBS for this program!

  • marika

    I was intrigued when i saw this film. I raise puppies for Guide Dogs for the Blind, and was happy to see that PBS is encouraging the help of dogs in the medical field. I also noticed that many of you who posted previously were looking for organizations through which to receive a service dog. there are MANY out there, worldwide. in the U.S. one of the largest organizations is Canine Companions for Independence ( they provide dogs to a variety of people, who have varying health issues- al at deferent levels- from seizure response to wheelchair assistance to companions. specifically for diabetes- i would recommend Dogs for Diabetics ( Or go to the Delta Society’s page ( as they have links to many, many more organizations.

  • jeannie

    We have a xolo (mexican hairless) who alerts me when my husband has low blood sugars in his sleep. This breed was recommended for our needs (a low maintenance dog, sensitive & devoted. We told the breeder of our intentions (medical alert dog) and she picked a dog whose personality she thought would fit the bill. I can’t say enough about our Lula. Suffice it to say that my husband would not be here today if it not for her alerting.

  • pam

    are there any dogs that can help with kidney failure?

  • MI

    My adult son, 48, who lives with me has seizures. I am most interesting in finding out about dogs that maybe can alert us. He has been battling seizuers for 12 years and the doctors can’t seem to find the right med combination. Can you tell me who to talk to or call. Thank you.

  • Ralph E. Price, R.N.

    How can I get involved, professionally, in a program which supplies medically trained dogs to a variety of patients? I am seeking employment opportunities in this area. I am currently employed as a critical care nurse working in CCU full-time but want to switch my focus to trained medical dog program.

  • william ruemmler

    i have heart trouble,had a 5 way bypass,when i work outside my pomaraneon is always with me if i do to much he will run in circles, bark at me,if i do not stop he will proceed to take little bites at my hands or legs,i stop and a few minites later i will feel like i am going to pass out,some times i will be real bad he will stop me before i go to far,shorty is my best buddy he goes with me all the time .

  • Judy

    I have a Seizure Response Dog, not many dogs can sense a seizure coming on but I do believe mine can, he has saved me from terrible injuries on many occassion and also saved me from being hit by a car in the middle of a cross walk. He always knows when I’m seizing and does his best to make me lay down (sometimes I can be a bit hard headed in that area)..They are awesome companions, friends and working dogs..loyal to the very end!

  • julie

    what dog would be good for a mentally ill young adult male

  • teri

    The other night my sister was visiting and her dog would not leave me alone. She was constantly in my face wanting attention (I thought) We went to bed and I had an epileptic seizure There is no doubt that the dog knew something we did not. That dogs father was the same way.

  • Carolyn Sexton

    Are there dogs who sense impending strokes? If so, what breeds to look for? How do I get in touch with people who train such dogs? Any info will be appreciated.

  • Rebecca Livas

    About a year ago my Min pin would not stay out of my moms face. He followed her every where. We ignored his behavior and he got mad and Peed on my couch.

    A few weeks later we found out that her Lung cancer was back and it was stage 4. It’s is possible for dogs to train them selves. Could he smell cancer in anyone? Or is it because he’s so close to my mom?

  • Shelley

    I love what these kind people are doing with their time, taking time to help others like myself by training these wonderful animals to be furry little helpers. They are a gift from god and so many others that help out. I just wish I knew more about all this when I raising my German Shepherds and Shelties, maybe I could of helped out by donating some of my puppies. I know I have been looking for one of these wonderful dogs and wish I knew of more places I could look for one. Please keep up the great work..

  • stinkybug55

    dogs r another word for happy

  • MaryClaire

    I’ve had migraines for forty years and my mastiff, Sammy, for 10. She is well loved by all five of my children and well fed by my husband! In April when the headaches started coming almost constantly and I was put on seizure medication to control them she started shadowing me everywhere I went. We live cozy ,in a 1500 sq. ft. doublewide so that means if I got up and moved 10 feet, so did she. It seemed a bit obsessive, given she could still see me and she was in obvious discomfort every time she would roust her old bones to move closer. This included following me into the bathroom and smelling by breath as I told her she was being weird. Then it got a little weirder, because as I wiped after urinating she assertively stopped me with her head and thoroughly sniffed the toilet paper. Once satisfied, she backed out of the bathroom (she is too big to turn around) and left me alone in stunned silence. She repeats this performance every time I forget to close the door, and has kept due diligence with her shadowing as well.
    As the summer went on I felt less and less well, was having more headaches despite taking the highest dose of the medicine allowed and had dropped 50 pounds unintentionally. Just after my 50th birthday I was diagnosed with Giant Cell Arteritis, a dangerous autoimmune disease that commonly is diagnosed because it takes the patients sight suddenly. It can also cause a whole host of other problems that include stroke, aortic dissection, scalp necrosis, etc. and since most people who get this are in their 70-80’s, I feel profoundly blessed that they caught it, that I still have my sight and that I am on the mend.
    And I can’t help but think that Sammy knew full well, way back in April, that things were not right with me. She was doing what she could. What she always does. She was standing watch. My good, obsessive, weird, old dog.

  • Frankie Graves

    I had watched this show by accident, and this is one of the best shows that i’ve ever seen. I’ve seen other dog programs, but this one was showing the entire process from beginning to end. That to me was great!

  • Doggielover

    It is so amazing what these dogs do! Great point, Frankie! Lots of times I (and others!) see good nature programs on accident!

  • vato loko

    que pasa

  • tal dane valor


  • Vivian Manczynski

    It would be wonderful if there a dog that can sense low blood sugar coming on. I’ve had type 1 for 43 years and if i can pair up with a dog who can sense the low blood suger, boy I would love it.

  • benny Brock

    our brother is 55 years old , lives alone and started having seizures when he became an adult. He has had
    fractured ribs, fractured left orbital bone and A brain bleed. The other day he had 2 seisures close together.
    He wants his independence but it’s getting harder to leave him alone. He is 6′ 5″ and he falls either straight
    forward or straight back never bending his limbs. I have heard of the dogs that can detect seizures. I want to
    know how expensive they are and what we need to do to get info on them? Where are the dogs trained? I appreciate any info someone can give me on this.
    Thank-You in advance,

  • Matthew weidl

    How do the trainers teach the dogs to sniff out cancer



  • Rishma

    I am 13, and I have type one diabetes. I have some problems noting when my sugar levels are high and low, and would really like to know a little bit more about these medical trained dogs and how this would help me.

    I would also like to know what the cost would be roughly, and how long would it take to receive the dog if I live in the UK.

  • Diane Ives

    Here’s some websites:;;; Canine Campanions for Independence (; and books: Dr. Allan Schoen (DVM), “Kindred Spirits”: Dr. Rupert Sheldrake (PhD); “Dogs Know When Their Owner is Coming Home”; Frances Ruffin, “Medical Detective Dogs”; Pat Shipman, “The Animal Connection”. Does anyone else have suggestions for books or websites about medical dogs/animals?

  • Debbie

    What is the behavior of a medical dog? I know someone who says there dog is a medical dog and I am not sure I believe them. The dog acts like any other dog. He is kept on a long leash and goes about sniffing and pulling on the leash. He never sits still. He is a good dog. He will go to anyone to get petted.

    Thank you

  • Geneva

    My husband is recovering from a brain annurism and while in a coma to treat the annurism, he had two small stokes. He is fully mobile, but suffers tasking difficulties and memory loss. I’d like him to have some independance. I think it would be extremely helpful to his recovery especially if he (and I) could help train the dog along with providing it a loving home. Who could I talk to to see if thisan option and if so, how to get it started?

  • Robin McDaniel

    It would be a wonderful thing to know how to get an alert dog. I’ve had epilepsy for 34yrs. and never been able to sense a seizure coming. Disabled I am now but a life is what I want. If a person could be blessed to share one with someone that cares enough to be beside them it would be worth everything. Someone please tell me why we don’t have those special animals for people like myself. I have read all of the articles and would pray that some people could work with me.

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  • Michelle W

    I have always loved dogs, anything I can watch or read about them I will. My parents don’t like sitting with me when we watch or go to a dog show because I can name every breed.

    I am even more in love with dogs now as I have a medical alert and hearing service dog. She was suppose to be my pet but at nine months old she alerted me to my very severe panic attack (I black out from them and I can not tell when one is comming on) due to a severe nervous breakdown. I could not drive, go shopping own my own or do anything else (I was 28 yrs old and looking at being dependent on someone the rest of my life). I also am hard of hearing and can not hear anything from behind and without my hearing aids I can’t hear much.

    I was very lucky, my pups basic trainer, trained service dogs, and when I told her what my pup did. The trainer started working with me and her for 2 yrs to train her to be a SD. Moose is now 6yrs and has saved my life twice since her first warning and numerous times she has gotten me to a chair or bed when my medication does not work so I will not pass out and hurt myself. My hearing is becoming worse and she knows the days I need her ears more.

    We have been together as Handler and SD for 5 yrs now and I don’t know what I would do without her. She isn’t a large SD, she is a 10lb yorkie/poodle SD.

  • diedre chase

    i looking for place to that have dogs for the hearing impare and the deaf. i have poor hearing with and with out my hearing aids. do you know where i can go? please help me? thanks for your help.

  • Martin

    Does anyone knows about a reputable organization in Houston TX, or in Mexico for seizure dogs? We are considering the possibility of getting a dog for our brother who lives in Mexico. Thanks ind advance.

  • Sherri

    I watched your show on dogs that changed the world and dogs by design. I am a animal lover, but these two shows made me see how incredible dogs are. We have taken these animals genetic make up and twisted them in to what we consider to be our perfect pet. Yet in spite of that they are still devoted to us. They are willing to learn new tasks in order to help us achieve a better life. They are even willing to put their life on the line to procect us. How incredible is that. All dogs deserve a loyal and devoted master who treats them with love and respect. I truley hope all dogs go to heaven.

  • Lori Candilora

    I also have an adult son living along haveing grand mall siezures. He had one in the shower today . How do I find out more on these dogs?

  • Dee

    My beagle, Penny starts barking and goes up to our other dog, Buddy a minute or so before Buddy actuallyTy has a seizure. Buddy seems to be perfectly normal, just walking around. Penny will start barking and coming up to Buddy and then Buddy will seize. Penny always seems to know before hand. Can’t explain it

  • Eileen Geraci

    Our dog Belle has never been trained but is very sensitive to oncoming storms/danger and also medical issues. She is extremely sensitive around my Dad who is diabetic. She watches him like a hawk and we know when he is not right or his sugar is running high or low because she acts differently. Follows him, shakes. We call her the nurse dog and we joke about it but when she alerts us – we always make sure he is okay! One weekend we were visiting and she was charging my dad and hitting him in the leg with her nose – we were joking about it that she wanted him to sit down because he was unsteady. The next week my father found out he had a blood clot in his leg. We will never take her “signs” for granted again.

  • Megan H.

    I have been a type one diabetic for almost 25 years (diagnosed when I was 7) and have had a problem with low bloodsugars in the middle of the night. Recently, my husband and I adopted a mastiff puppy named Brutus. My husband and I took shifts in taking Brutus out and my husband ended up with the night shift. So when Brutus (then a five month old puppy) started whimpering and pawing at me in the middle of the night, my husbandd knew something was wrong. He quickly woke me up to test my bloodsugar and learned my bloodsugars had dropped dangerously low. At first, we thought this behavior was a quirk or one time event… but over the past year, Brutus has woken me up countless times – even going to seek out my husbad in another part of the house when I had a hypoglycemic attack in the middle of the day. Having Brutus in our lives has been a miracle and even though his size (140 lbs. at one year old) can take a little getting used to,I wouldn’t trade the happiness and peace of mind he has brought to our family for all the world.

  • Jill

    I have rheumatoid arthritis and my Australian Cattle Dog seems to be sensing my flares before they start. He has been licking and mouthing my hands for a couple of weeks now, when the flare got worse ,he stopped mouthing but is still licking my hands, feet and knees. These are areas known to cause me the most pain. I have had a hard time digging up more info on this. He was acquired as the family pet but quickly “chose” me.

  • Taira

    Hi my name is Taira and my spaniel woke me up tonight she wouldn’t let me go bk to bed I have many medical problems also she sniffs my breast I’m not sure y for people out there u can buy a puppy and take it to a service dog trainer as some places have very long waiting lists

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