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Featuring Demian Dressler, DVM and Sue Ettinger, DVM, Dip. ACVIM (Oncology), authors of The Dog Cancer Survival Guide

An Antibiotic for Dog Cancer

Updated: March 20th, 2019

Antibiotics are normally used to treat infections, but not many know that there are anti-tumor antibiotics.

One of the cheapest, safest, and most easily obtained through a vet? Doxycycline.  Now, doxycycline is not a dream antibiotic.  It actually has fairly limited use as an antibiotic.  Some use it for dental infections, but it is most commonly used to treat certain blood parasites.

Some exciting news about doxy?  It has anticancer effects!

Doxycyline helps suppress angiogenesis (new blood vessel formation that feeds tumors and robs the body). In this way it slows tumor growth. It blocks enzymes called matrix metalloproteinases (MMP’s) that digest the tissue around tumors, allowing new blood vessels to be formed. Check it out here.

Not having access to as much blood supply, the cancer cells are less able to metastasize through the circulation.  This lessens the spread of some cancers. Read more.



In the lab, this drug can induce apoptosis (normal, healthy, programmed death) of cancer cells.  This is a direct action on the cancer cells, and may have some usefulness in cancers like lymphosarcoma. Here’s the abstract.

In humans, this drug has been a disappointment for cancer treatment.  But in dogs, according to Greg Oglivie, MMP inhibitors (of which doxy is one) combined with chemo for lymphosarcoma improved survival times in some older dogs in double blind, placebo-controlled clinical trials.

Although this is a prescription drug, it is widely available and inexpensive.  It can be used with most other agents used in fighting cancer, and is quite safe.

When young dogs take doxycycline, some may develop yellowed teeth. It may cause abnormalities in the cartilage of developing pups in the uterus, so do not give it to pregnant dogs.  It should not be given with calcium-containing foods as this may lessen absorption of the drug.

Best to all,

Dr D


Leave a Comment





  1. Edith on March 29, 2009 at 5:43 pm

    Dr. Dressler, do you know anything about noscopine? My 14 y/o labradoodle is 2 ys 2 mos post lymphoma diagnosis. He had a NC State multi-agent chemo protocol in 2007, went into remission within a month. Came out 12-07 and went on single agent doxorubicin. Almost immediately went into remission which held until 11-08 when he developed 4 lumps in various places on the right side of his body. Tried procarbazine for 3 cycles. After the 1st, the lumps went away, but shortly after the 3rd began, a new lump developed. Switched back to doxorubicin. Lump went away in less than a week, but I’m scared of the doxo. Read about noscopine, but cannot get human researcher or the company they are working with to return calls/email. My vet oncologist wanted me to find out about any canine safety studies which may give us dosage info. Do you have info about this European OTC cough medicine ingredient? Thanks.

  2. John on March 29, 2009 at 3:13 pm

    You apparently have not read the latest research on antiangiogenic drugs, they do not suppress blood vessel formation, just the opposite! Use of these drugs actually enhances the integrity of tumor blood vessels, and can promote faster tumor growth.

    http://ucsdnews.ucsd.edu/newsrel/health/11-08Tumors.asp

  3. Joanne on March 8, 2009 at 8:21 am

    Dear Dr. D.,
    Benny has Mast Cell Tumours and he has had the cortisone injection (the one you recommended and I cannot remember the name….intra…tra..)and the tumour did not shrink much. Today it bled a little and my husband administered the powder form inside a Yunnan Baiyao capsule to the tumour. We also gave him a the other half of the capsule in some liverwurst. What are your opinions on this particular supplement being used in dogs with MCTs? We are willing to try anything to insure that his quality of life remains as good as it is right now. He eats well and enjoys his daily CANINE LIFE muffin and is very happy on walks.

    Thanks,
    Joanne

    • Dr. Dressler on March 9, 2009 at 4:16 pm

      Joanne-
      sometimes we look at a lack of growth as success!!
      Now, I am not a Chinese Medicine expert by any means, but I believe Yuannan Baiyao is more suited to other tumor types…another thing that some have used is topical quercetin (powder on the tumor). I have not but it is an option. Discuss with your vet as usual!

      D

  4. Val on February 14, 2009 at 5:07 pm

    Dear Dr.
    I have started our 5 year old golden mountain dog on Dichloroacete (DCA). He has lymphoma and was diagnosed Jan 14. He is on prednisone, 8 – 10 mg of DCA, B100, magnisum 100 mg. 500mg of evening primrose and baytril. I am wondering if doxycycline is a better choice of antibiotics. He is doing much better now that he is on DCA and I hope that this note will help other people with cancer in their dogs to go to the DCA site and see what miracles are happening with its use, even if it is only in trials… you can still order it from buydca.com.
    Good luck eveyone with your pets.
    Val

  5. Gail Casey on January 22, 2009 at 8:20 am

    Dr. Dressler,
    My mixed rescue 12 year old pup was diagnosed with nasal adenocarcinoma in Aug. 2006. After consultation with a well respected radiologist/oncologist here in the LA area, he underwent surgery and radiation (newer protocol due to improved equipment). His tumor has reacurred but Metacam, fish oil, Agaricus mushroom caps, Yunnan Paiyao, Glucosomine and immune support along with a partial raw diet (he can’t handle total protein) have kept it growing slowly. He still loves his walks and seems happy. Recently his sneezing increased and occasionally he again has a small bit of bloody discharge. Is doxycycline recommended for this type of cancer? I realize I have had him far longer than is usual for this type of cancer and for that I am grateful but would still like to do whatever I can to keep his quality of life good. Any other supplements you can suggest?
    Thank you.

    • Dr. Dressler on January 30, 2009 at 8:17 pm

      Gail, this (like many questions I get here) has a very long answer, which is why the e-book is coming. Short answer though:
      Doxycycline is definitely a thought, especially with the epistaxis (nasal bleeding). The studies were not done with nasal ACA but that does not mean it is not a good option. Discuss with your oncologist. I would consider it for sure.
      Best of luck,
      D

  6. Karen on January 19, 2009 at 5:54 pm

    Dear Dr.Dressler,
    My 10 1/2 yr golden was diagnosed 9/4/08 with a brain tumor/hemangioma, preempted by 3 grande mal seizures on 8/30/08. His prognosis was 3-6 months. On 2/4/09 it will be 5 mos. We are not doing chemo, radiation, or chemo, but we are do phenobarb and prednisone. He is still a happy boy, walking 1-2 miles per day and still (thank God) seizure-free. We are also doing Vit C, Fish Oil, Astragulus, Pignogenol, Green Tea, CoQ10, Milk Thistle, and Sam-e, along with Tissue Tone, and Chlor-oxygen and glucosomine for his arthritis. Any other recommendations?
    Thank you so much for your sharing of your knowledge and your wonderful attitude!
    Karen Bender
    Springfield, NJ

    • Dr. Dressler on January 30, 2009 at 8:26 pm

      Karen, I am sorry to hear this yucky news. Hm. You might want to consider methyl jasmonate. I’ve never used in personally in dogs but check it out with your vet/oncologist. It is inhaled from a steam-type vaporizer. Hard to do maybe, but depends on your dog. Check out Stephen Martin’s blog Grouppe Kurosawa for some stuff on this. Also definitely look into Lutimax and discuss with your vet/oncologist.
      Good luck,
      D

  7. Michelle on January 19, 2009 at 8:27 am

    My dog had mast cell tumors stage I and is currently on Leukeran. Is this antibotic something that I should consider giving her with her chemo treatment?

    Thanks, Michelle

    • Dr. Dressler on January 19, 2009 at 3:18 pm

      Hi Michelle, you might want to check with your oncologist about the white count. If the count is low, I would certainly consider it, after discussing with your vet or oncologist. My e-book will be answering these questions in a lot of detail.
      Good luck
      D

  8. Shavonne Harpole on January 19, 2009 at 8:13 am

    Dear Dr. Dressler,
    My four year old english bulldog was diagnosed with lymphoma in July. She started the 5 drug chemotherapy protocol for 19 weeks. She went into remission after the first treatment and appears to still be in remission. Is the doxycline something I should add to her treatment when the cancer comes back or currently while she is still in remission? My dog means everything to me and I would do anything for her. Please give me your opinion. I really respect your work in dog cancer and wish there were more of you.
    Thanks
    Shavonne

    • Dr. Dressler on January 19, 2009 at 3:14 pm

      Hi Shavonne,
      I would perhaps consider some of the other supplements discussed here, making sure you have consulted with your vet or oncologist. Perhaps EGCG, Curcumin, fish oil,ginger would be some considerations. You might want to look into my upcoming e-book too, the dog cancer survival guide,which will be available for downloading within 2-3 weeks, which answers questions like this and presents a full spectrum plan (diet, supplements, and more). It is the first of it’s kind, so I am pretty excited about it! Thanks for the compliment by the way!
      Best,
      D

  9. Donna Becker on January 19, 2009 at 3:51 am

    I am sorry you didnt get to say good bye for him..that must have broke your heart into a million pieces…

  10. candice on January 8, 2009 at 7:40 am

    my boyfriends mom took his dog to the vet because we noticed he had a lump or 2 under his chin and they gave him antibotics and said give them to him until they are gone and wait and see if lumps go down-about a week or 2 later we come home and she put the dog to sleep, we didn’t even get to say goodbye-we didn’t even know she was going to do it. They said he had cancer of the lyphnoids. He did not seem at all like he was in pain and I have yet to find out how long he had it or when it had developed. Why would the vet be ok with putting the beloved dog down? his mom has alot of issues, but why do it if the dog didn’t seem like it was suffering.

    • Dr. Dressler on January 15, 2009 at 12:26 am

      Candice,
      perhaps they wanted to make sure they prevented suffering that was going to happen in the future, so they made sure there was never any negative life quality from the cancer. This is my only explanation, but it could make sense.
      Hang in there,
      D

      • Jill on May 23, 2011 at 12:55 pm

        My 9 year old lab has been diagnosed with lymphoma. He mostly has good days wanting to play ball and go for walks at a slower pace then usual but still active.
        He is currently on a 5 day treatment(round two) of cyclophosph and prednizone daily. He’s eating like a champ(I cook a high protein/high healthy fat diet for him).
        white cell count came down from 42,000 to 5,400 but his glands are swelling again. would this doxycycline help him? We’ve been treating him for about 4 weeks now.

        • DemianDressler on May 25, 2011 at 8:56 pm

          Dear Jill,
          I am a bit worried about your lab. I would be reaching for more than doxycycline if his glands are getting larger. The chemo should be adjusted by your vet or oncologist. Also, there are a lot of other steps that you could be taking. I assume you are using apoptogens, omega-3 fatty acids, immune support, and the other steps in the Guide??
          I hope this helps
          D

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