Does cancer smell? Can people smell cancer?

If you or a loved one has recently been diagnosed with cancer, you probably have a million questions. Your head may be spinning with all the new words you hear and the treatment options you need to decide about. Even with all that going on, you’re probably just as worried about how your day to day life might be affected.

There’s a lot of technical and medical issues to ask about, and some of them may seem too small or silly to ask. One question that newly diagnosed cancer patients often wonder about is “Does cancer smell?”

There are two reasons for asking this question. Patients and family members sometimes wonder if they could have found the cancer sooner by being more vigilant about odors. Patients are also concerned that their illness may make them smell bad or give off an unpleasant odor, offending people around them.

Rest assured that you are not alone in wondering about cancer smell. Your medical team has probably heard this question at least a hundred times or more. And while it may seem like a simple question, the answer is actually not quite so simple.

A Cancer Smell: Folklore or Reality?

There are many stories about people who claim to be able to smell cancer, and it may very well be true. Different people have different sensory capabilities. Just as a professional “nose” in a perfumery may be able to easily discern every subtle note in a delicate fragrance while the rest of us can only guess at a limited ingredient list, there may be people with the ability to sniff out cancer.

Before the advent of modern medicine, using odors on the breath was an accepted way of diagnosing disease. Doctors still use the distinctive fruity odor of a diabetics’ breath as a marker of the disease. Patients with other diseases, including kidney disease, diphtheria, typhoid, tuberculosis, liver disease and cystic fibrosis, are said to have characteristic scents. Certainly no one would argue with the smell of gangrene as a diagnostic tool.



However, most of the stories about people who can allegedly smell cancer center around somebody’s grandmother, an experienced nurse or a lucky—or unlucky—bystander. Few of the stories agree on the actual aroma of cancer, which may mean there isn’t one, or it may mean that it varies by the type of cancer.

Even though the stories resemble folklore more than scientific reality, there may still be a grain of truth to the legends. There’s at least enough truth in the stories to have spawned several scientific research studies and the quest for an artificial nose, which we’ll examine in a later section.

Animal stories also lend credence to the idea that cancer has a distinctive odor. There have been documented cases of dogs who are able to correctly identify the small number of cancerous skin or urine samples in a large group of samples that contain both healthy and cancerous samples. Dogs have been known to pinpoint the affected area of a cancer patient’s body, lending credence to the theory that cancer smell is unique.

Dogs are also credited with alerting their owners to cancerous lesions on various parts of the owners bodies. In these stories, the dog is generally so insistent on directing its owner’s attention to the spot that the owner eventually seeks medical attention, only to discover that the spot is indeed cancer. These stories are so pervasive that scientists around the world have begun experiments to see if dogs can provide an early warning of potential cancers, or point the way toward finding a non-invasive way to spot and identify cancers.


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Scientific Research Studies

Many medical researchers believe that cancer is a metabolic disease, one in which the normal cell regeneration process goes awry rather than an invasion of a virus or bacterium. Since there is no “invader”, the exhalations of cancer patients contain the same substances as those of people without cancer. As a result, scientists need to identify typical ranges for each substance in both healthy people and people with cancer.

This is not as easy as it sounds because there are more than 250 substances in the air that people exhale, and the proportions vary based on many air quality as well as many health conditions and even diet.


Some scientists, such as Hosam Haick in Israel, are using nanotechnology in research trying to pinpoint the compounds that possibly indicate cancer in exhaled breath. The research has been published in the British Journal of Cancer, and demonstrates that the artificial nose is able to detect cancer in the exhalations of people who suffer from head and neck cancers.

The Atlantic Cancer Research Institute is also working to identify cancer based on exhalations. Their research is focused on lung cancer and uses infrared laser technology to analyze the exhaled compounds. Clinical trials are currently in process.

Researchers at the University of Pennsylvania have identified a characteristic odor associated with basal cell carcinoma, a common and easily cured cancer. They are continuing the research to identify a characteristic odor for the deadlier melanoma skin cancer. Further refinement and commercialization of this technology will provide early identification of skin cancer and also help to eliminate unnecessary biopsies. This research is still several years from being commercially viable, but holds great promise.



Despite their progress, none of these technologies have proven that cancer smell is characteristic and detectable by humans, although the research certainly suggests that cancer changes the chemical composition of exhalations. It is not too far of a stretch to assume it might also change the composition of sweat, tears or other bodily fluids, making it more likely that it might be possible for some people—those who have an exceptionally acute sense of cancer smell.

Animal Studies

Dogs have an astonishing sense of smell. Their ability to identify odors and scents is 10,000 to 100,000 times more powerful than humans are capable of identify. In fact, dogs can identify scents with just one part in a trillion (PPT). Dogs have 300 million olfactory receptors in their highly sensitive notices. Humans average a paltry 6 million. No wonder they catch more scents than humans do. Scientists are testing to see whether their incredible sense of smell can lead to early identification of cancers.

Two dogs in Italy have been trained by scientists to identify prostate cancer in urine samples by scent alone. The dogs are able to do this with more than 90 percent accuracy, exceeding the accuracy of current PSA blood tests. They correctly identify prostate cancer samples even when the samples are mixed with samples from patients with other types of cancer. This implies that each type of cancer may have a unique, characteristic odor. This research was published in the Journal of Urology.



Penn Vet, which is part of Pennsylvania’s School of Veterinary Medicine, is working with dogs to identify ovarian cancer by smell in blood samples. The intention of the research is not to use dogs as diagnostic tools, but to help identify the compounds that signify cancer, but which people, with our limited sense of smell, can’t identify. The hope is that once identified, other researchers will be able to use the information to create an artificial nose for clinical detection.

A “proof of concept” study published on set out to determine if dogs could identify bladder cancer by the smell of the patient’s urine. The dogs were able to correctly identify bladder cancer about 41 percent of the time, a greater proportion than would be expected by random chance. This seems to provide proof that bladder cancer has a detectable odor, although not one detectable by most humans.

Researchers and medical professionals continue to promote animal studies to help identify the compounds that identify cancer. It’s unlikely that dogs will ever be used during diagnoses or physical exams. Their ability to help identify compounds and provide a roadmap for scientists is a more probable path for dogs and their incredible sense of smell.

Personal Concerns

cancer smellOne of the reasons people commonly ask if they can sense cancer smell is because they are concerned that people will smell it on them. In our society, any bad smell can be embarrassing, but you do not have to worry about people around you smelling your cancer.

While science will soon be able to identify the compounds that make up the characteristic “smell” of some common cancers, in most cases the concentration of these compounds is too low to be detectable even by people nearby. Normal levels of everyday hygiene should be adequate to ensure that you do not smell like cancer.


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Michel completed his Oncology training at the University of California at San Diego and specialized in cancers of the kidneys, prostate and testicular cancer at the MD Anderson Cancer Center. With the constant changes in diagnostic tests and treatment options, he believes every patient should have access to the highest level of care.

About Michel Choueiri

Michel completed his Oncology training at the University of California at San Diego and specialized in cancers of the kidneys, prostate and testicular cancer at the MD Anderson Cancer Center. With the constant changes in diagnostic tests and treatment options, he believes every patient should have access to the highest level of care.

39 thoughts on “Does cancer smell? Can people smell cancer?

  1. Hi I have a relative has kind of recovered from pancreatic cancer it’s been 1year now but he has a lot of bad smell we don’t know why could u please advise if possible,
    Thank you

    1. Dear Lydia, thank you for the message. Chemotherapy can result in metabolites that are secreted through the skin, urine or with bowel movements. However, those should be improving within 6 to 9 months. A full year is rather on the late side. Is the smell getting better, worse or same?

    2. bad smell ??? on men it is lemony bitter odor
      also the smell of chemotherapy by products as perspiration & urine which is inevitable but if you stop it will go however bittery lemon odor on men or Trimetylaminuria smell to go you have the be cleared of the condition <<< microbiologist / chemist

  2. I believe you can absolutely smell cancer. Smells like fermented fruit. After successful chemo the person smells as if they have been bleached and fabric refreshered. You will probably throw out the bedding. When the smell starts to come back again Even before the numbers are alarming there’s no doubt what you are smelling.

  3. For more than a decade, I’ve had severe nasal polyps and have had to take MucinexD and Afrin, daily. My wife had her thyroid removed, about a week ago, due to cancer. Since then, my sinuses have been clear! That’s the only change we’ve made. Still using the same soaps, etc.

  4. Hello I been tested free from all stds but one thing bother me is lumps undermy skin i can feel them more see them. This been two yrs i noticed more so felt now i have a smell it stays in the room even when im not there could be cancer also i will get a diagnoses on this symptom

  5. Hello I been tested free from all stds but one thing bother me is lumps undermy skin i can feel them more s/e them. This been two yrs i noticed more so felt now i have a smell it stays in the room even when im not there could be cancer also i will get a diagnoses on this symptom

  6. Cats can smell and locate cancer too. Eighteen years ago my cat started climbing on top of me at bedtime and pushing hard on a particular area of my breast. I’d throw her down and admonish her, but she persisted for two weeks. Finally I understood what she was telling me and made an emergency appointment for a mammogram. The initial x-rays showed nothing but I insisted I had cancer and begged the technician to continue filming till it was found. It was growing in all my milk tubes and had just begun to spread at the exact spot where my cat had been pushing . Following a double masectomy and rebuild, I’m still cancer free after 18 years. Listen to your pets because they may be trying to save your life.

  7. I can smell my cancer. It drives me crazy. My husband can’t nor my dajghter but I smell it 24/7. It has a distinctive odor, I can’t explain it other than its awful. It’s like its coming from within cause I dont smell it on my underwear. I have vulvar cancer and when I’m just sitting I can smell it coming off of me. Ive had chemo, radiation and surgery and still have it. I dont know what to do but I can take showers nonstop and still smell it. I told my oncologist and he said its the cancer that I’m smelling. Why doesnt my family smell it?!

    1. It is one of two things! They have a bad sense of smell or they are not being honest with you because they do not want to hurt your feelings.

  8. I have been complaining about an odor on my husbands pillow for months. No change in soap or shampoo, and I cannot explain the smell, it is totally different. I bought new pillows, constantly change bedding, but it always comes back. I thought it was due to getting older and just body chemistry change. 4 days ago he was diagnosed (biopsied) with cancerous tumors on his neck. We are told we need to begin radiation and/or chemo immediately and are meeting with the doctor tomorrow to discuss the treatment plan. I am kicking myself for not insisting a visit to the doctor sooner. In hindsight, there are many other signs that should not have been ignored for instance a raspy voice, increased sinus which we blamed on the weather. I will add that our oldest cat has had the habit of sleeping up by his face and she wakes him at night licking his face, lips and neck….the left side where the lumps were found. We laughed about this, but now it is not so funny. We’ve had cats throughout our 30 years together and have read stories about how cats (and dogs) are known cancer detectors….just never put the pieces together. You have nothing to lose by getting checked out if you are suspicious of an odor. You do not have to be a doctor to let common sense tell you cancer growth happens due to changing cells and this would undoubtedly effect your body chemistry, hence the smell.

    1. I have a lymph node on my left side of my neck for a few months then I started getting the night sweats and it would smell like milky or vinegar smell and it’s still going on shortness of breath a cough chronic fatigue I already have fibromyalgia lost my job and insurance because of missing so much send as I can I will go to the doctor thanks for sharing your story I was looking up to see if anybody else was having a odor in there night sweats I just get drenched at night have a blessed day thanks

    2. Jackie, Can you please explain what it smells like, because my fiance puts out an odor as well. His smell is like sweat and drool and iron combined. He told me that his Dr mentioned something about him having thyroid cancer.

  9. Its uncomfortable and I know that many of you find my experiences surreal or peculiar but I will write it anyway Fist I have to say that I am not a layman studied microbiology at higher education level …. Anatomically I have a longer and bigger nose I have befriended over 200 women due to my work etc and sometimes intimately in different geographies etc It always baffled me to smell Trimethyaminanuria (TMAU) / fishy smell in women who later developed cancer … The frequency of this peculiar odor was quite high in each 10 there was 8 TMAU and that level of frequency could not be attributable to hygiene .Besides following their later life story almost all proved they developed cancer of various sorts mainly reproductive area or breasts . Finally I thought of searching this phenomenon and to my horror I found that I was right in my suspicions… I am amazed that men have not earlier put 2×2 before .. I am sorry but this is my experience Another odd thing I heard again from a woman that her late husband was smelling unusually bitter lemon long years before years the diagnosis… So what do you say ???

  10. I can most definitely smell it and whatever form of cancer I can smell most definitely isn’t coming from an exhalation. The scent follows them and can even linger in the air for a while. I started noticing the smell while I worked in a hospital lab, I would smell it on certain people. that would come in. After quitting there I would smell it on a couple individuals every now and then but never could figure out what it was that I was smelling. Years later I took a job at an Oncology office and was smelling it frequently. I was finally able to put 2 and 2 together. I’m still not sure exactly what form of cancer I am smelling (I never looked at their diagnosis due to privacy concerns) but it is not all cancers because I only smell it on a few people. I have also asked others if they can smell it while I am smelling it and they look at me like I’m nuts. But I also have a very sensitive sense of smell and can smell sweat on seemingly dry individuals from yards away. It is an awful smell though.

    1. No – smell starts long before I mean 10 or more years before the actual diagnosis A decade or so ago I had a talk with a Medical Doctor friend of mine he was was mentioning similar findings in private though he was not expressly correlating 2 seemingly unrelated events . I dont think it is ever mentioned in clinical or medical circles anywhere either …

    2. I can smell it too. I’ve told my doctor’s, and they think I’m nuts. Nobody else that I know , can smell what I can. I feel like I’m crazy. I’ve told over 20 people, turned out to be pre stages of different cancer.

  11. smells like Trimetylaminuria TMAU = every time in women and lemony bitter odor in men full stop ; experience of a microbiologist / chemist for 30+ years

  12. So after reading this I do not find my questioning my sense of smell any longer. I have been smelling an odd smell on my husband for at least the last 5 or more years. He too feels like he has an odor but takes at least one shower if not 2 a day. My question is how do you pose this to your loved one or to get a physician to listen to you about your suspicions and concerns??? Thank you

    1. 5 years is a long time and decreases the possibility of an actual tumor being the reason for the smell. I would encourage you to discuss age specific screening tests with your doctor. If further symptoms are noted and point to a specific problematic area, then these symptoms can be worked up further

  13. I believe dogs ? have noses & not notices. You might wanna hire me as your proof reader/editor lol just kidding -I thought you’d like to fix spellcheckers ignorance so you will retain your credibility;)
    Feel free to delete my comment after finding the boo boo …

  14. I am smelling an unusual odor. It is the same odor I smelled on my mother and Aunt and they both died from cancer. One from pancreatic cancer the other from lung cancer. I have a breast mass. I go back for a six month check-up in May. What are your thoughts?

  15. Yes I firmly believe that you can smell Cancer. It is difficult to describe, but has a bitterish smell. I have smelt this on a number of friends before they were diagnosed with Cancer.

  16. I can smell cancer, I knew my brother in law had it. It is a unique smell, obviously I never mentioned I could smell it. He was a very clean person who never drank or smoked, and no bad habits. I never knew it was cancer but sensed it was not right. He died shortly after. Since then I have been diagnosed with a golf ball sized brain lesion on the right frontal lobe. I had side strike by lightning 16 years ago and was knocked out. Since then my ST memory is bad, spelling and cognitive skills. Strangely my hearing is very amplified, light sensitivity and sense of smell is like a drug dog. When I walk down the laundry/detergent section I have a headache in seconds. Also perfume/aftershave and other. Apparently something has been switched back on everyone had In primeval times but don’t use. In the natural environment it’s a bonus but in cities/towns it’s a disability.

  17. I can also smell cancer. I am a Nurse Practitioner. It is a very distinct odor and honestly it smells the same to me on every person thta has cancer. I have confirmed my findings with an oncology nurse friend of mine. She concurs that she can smell cancer also.

  18. i too have developed a strange unpleasant body odor at 73.presently being treated for basal cell cancer of ears and had non hodgkins lymphoma 15 yrs. earlier. odor is very pugnant and unpleasant. ive thrown out bedding and a recliner thinking it from them . not a very pleasant odor. showering only removes odor temporarily.seems to be co ming from my whole body.

  19. I have recently developed a very strange smell when I go to the toilet for a wee I had a fibroid which was 900 gr being told it was just a fibroid and not to worry. I was left for 8 months walking round with it. A few weeks before the surgery to remove said fibroid this strange urine smell started. I’m six weeks post op and the smell is still there and on my post op check up I was told that I have a very rare malignant cancer. Could this be the strange odour? A CT scan has shown.
    That it has not spread through my body. I’m now waiting to go to London to see an Oncologist and start radiotherapy. Any thoughts? Many thanks.

  20. I am 58 and for the past 4 years I have smelled an odor on me that is hard to describe but very unpleasant. I have usually noticed it during the summer months, so I thought it was getting triggered when I get warm. I sometimes smell it when I get slightly warm, but other times I can be drenched in sweat and not smell it at all. I had considered the odor coming from my nose, but I don’t think it is. I went to the doctor twice and described it as a musty odor, but she could not smell it when I could. I can smell it on my hands and arms. I can shower, and a minute later the odor is all over me. It smells a room in seconds, and sheets and blankets.

  21. Hi, I can smell an odor from my brother, he is 60, has had a lot of sickness, lays in bed day after day only showers evey 2 days. I notice his room and bsthroom smell of this too and is slowly creaping further. It is a rotting, old sweat, bed head smell. He had a chest x ray where doctors saw scsring 4 years ago and recently coughed up black blood 3 times in the morning for 5 days then nothing more was coughed up. He is set to hsve. CT scan which I think will show cancer. It is hsrd to tell someone they stink snd get a shower, He does not seem to csre, He had this odor before and found he had crotch rot which he said is cleared up. The odor is so hard to explain but I feel like his head and upper body smells like the crotch rot. Could this mean late stage cancer rotting his body from the inside out?

  22. I am glad that I found this site. I volunteer at this place and many of the sheets donated have this app dd smell. I chaulked it up to being an old peoples smell(like maybe the sheets and towels got stale from sitting in the linen closet for years).I was smelling that smell on my bedding so washed every bit of it. I was diagnosed and treated for breast cancer but still didnt put two and two about the “smell”.My friend husband has leukimia and she asked me if there was a cancer smell. Also I had contact with another friends very young son that had colon cancer. When I hugged him I smelled the smell. It wasnt until then that I figured it out. Imwas at a Mexcan Restaurant and walked passed two people and I know one of them had cancer. I would never say anything to anyone about this. I recently was going to wear a sleeveless knit top that I hadnt worn since the cancer and it had that smell. I have since washed all of my clothes with regular soap and a cup of vinegar in each load.

  23. I work in health care and think I have smelled it…similar to moth balls? I thought it was just “elderly ” smell but noticed it in all ages when I worked on oncology floor

  24. I can smell the chemotherapy medicine. Happens the following week after his treatment. It’s such a strong smell that I would get sick to my stomach.
    I kept telling him it’s making me sick. So he asked his doctor and was told there’s no such thing.
    He continued on with many chemotherapy drugs . How do I know? The following week he would smell different. I would ask, “did they change your chemo?” This went on for months and each time I was right. Then when they placed him on the immuneo therapy chemo, (not sure of it’s spelling or pronunciation) but it was the worst that I have smelled. I was getting extremely painful headaches also vomiting from it. It turns out it was too high of a dose so they lowered it.
    The scent was so strong that I told him this could be the worst are the best for you because it’s making me very ill.
    After that his health declined at such a fast pace.
    Last night I found him in the chair slumped over not breathing with a very weak heartbeat.
    Turns out he took a heart attack.
    I was just told he isn’t going to make it past 24 hours, he’s on a ventilator with low blood pressure and still unresponsive.
    Prior to this, Took a three week leave of absence from work because there was a much stronger new smell. It wasn’t a chemo smell and I have never smelt a scent like this before. I don’t know what death smells like but if I had to label it. I would say death.
    I’m not crazy but I can guarantee if a variety of chemotherapy drugs were placed in front of me I can distinguish each one from another.

  25. Cancer does smell. Last summer, my husband noticed an “infected mole” on my back. Went to have it looked at, and it was a basal cell carcinoma, which had to be removed. Took a long time to heal. This morning, I had another “bad mole” removed and it was a melanoma. Both times, I kept smelling a very peculiar odor coming from my body. I have always been fastidious with body hygiene, so it wasn’t something related to that. I asked my husband if he noticed it, and he didn’t. I can’t even describe it; totally unique. As the first cancer area healed the smell faded away. I had to wait for followup to the second “mole” to be investigated, because of the Coronavirus stuff; I had to postpone and reschedule appt. for over 2 months. During that time, I began noticing the same odor again, and my husband was again oblivious to the “odor.” He was outraged that my diagnosis was delayed for so long, though. Even more so when the word Melanoma was on the post op data sheet that came home with me. The Dr.’s office gave me a copy of the biopsy report, and the words, “have the area excised immediately” blared out like a loud horn blowing- I have to return in 2 weeks to have sutures removed, and then in 2 months for a complete body check. I am going to keep a sharp lookout for any future “strange” moles and even more so to “strange odors!” When I noticed the odor, it seemed really strong, but not ONE person ever commented on any odors, even when I asked them if they smelled anything.
    I have been known to smell all sorts of things that others don’t, my entire life. It’s obviously something that not everyone has the ability to do.

  26. People smelling cancer on a person is definitely not “folklore”. Although, I can understand how some wouldn’t believe that its possible. People tend to discount what they don’t understand. I began smelling a putrid smell on my husband’s breath a year and a half before he was diagnosed with lung cancer. I took him to a dentist and a doctor to have them exam the inside of his mouth, and teeth. Neither of these two doctors could smell it. To me, it was overwhelming. I couldn’t even ride in a vehicle with him because it was that putrid. A year an a half later, they found a 6mm tumor on his left upper lobe. His treatment began in 2013. He is still alive and kicking. My adult kids have always said that I should find a job where this “mad skill” is useful. I would love to work in a hospital setting, but have no idea who I would even talk to about it.

  27. About five years ago I was diagnosed with stage lll breast cancer. Before I got the diagnosis I noticed that any time I bled my blood had a smell. The smell was like old coins or metal. Once treated with chemotherapy and radiation I no longer noticed the smell. However, I am now noticing this now again any time I bleed. Has anyone else had experience with cancers smelling like old coins or metal?

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