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

Vitamin C and Dog Cancer Update

Updated: April 13th, 2021

There is much talk on the use of vitamin C (ascorbic acid), in it’s various forms, for cancer treatment in the “alternative” medical community. It’s use in conventional cancer care is routinely ignored.

In the spirit of full-spectrum care and rational analysis, let’s take a closer look.

Due to some interesting observations, focus on vitamin C for cancer is still alive and well in the research community.  I’d like to separate the wheat from the chaff and give you some main points.

  • Vitamin C, given by mouth, does not have direct anticancer effects on cancer cells.  The concentration in the blood is too low following oral administration.
  • Vitamin C is known as an anti-oxidant.  While it is at lower doses, the anti-cancer effects at the needed super-doses are actually pro-oxidant. (For more  on these concepts, click here)
  • The way to create the doses needed (vaguely 1000 micromol/L in the blood) is by giving IV injections of the vitamin.  There are published protocols of this having success in a few severe human cancer cases, put out by the Canadian Medical Association.  These can be used with your veterinarian’s cooperation to formulate a plan.
  • In 39 people with terminal cancer, a study found that quality of life improved combining IV and oral vitamin C (less pain, fatigue, nausea, and improved appetite).
  • In a test tube, another study found that high doses of vitamin C killed cancer cells including lymphoma, mammary cancer, pheochromocytoma, kidney cancer, bladder cancer, lung cancer and glioblastoma cells.
  • There is a concern that low (antioxidant) levels (like those achieved from vitamin C taken by mouth) may, at least theoretically, reduce the effectiveness of chemotherapy and radiation.
  • Vitamin C may increase the odds of certain kinds of urinary stones (calcium oxalates) and should not be used in patients with this problem.

What to make of all of this?  When you are dealing with a life-threatening canine cancer, and your dog does not have calcium oxalate urinary stones, you should consider adding IV vitamin C to your dog’s treatment plan.  This is especially true if your dog is not receiving chemo and radiation.  Many more outside the box treatments can be found in The Dog Cancer Survival Guide.

Get your vet involved.  Be your dog’s number one health advocate! Even if your canine companion does not experience a dramatic remission, there is at least evidence that quality of life may improve.

Best to all,

Dr D

Leave a Comment

  1. Nina on March 29, 2012 at 12:31 pm

    Dr Dressler,

    My dog (55lb golden shepard/airdale terrier) was just diagnosed with
    hemangiosarcoma. He has a cantaloupe sized tumor on his spleen and it has spread to his liver. I was told there was nothing that can be done and just make him comfortable. I can’t accept that there NOTHING that can be done. Any advice?

    Thank You!

    • Dr. Demian Dressler on April 12, 2012 at 2:49 pm

      Dear Nina
      that is not really true.
      Chemo can be considered, as can apocaps, neoplasene, yunnan baiyao, modified citrus pectin, bet glucans, the dog cancer diet, just to name a few. I would read the Guide which is designed to help answer this complex question.
      I hope this helps and please check with your vet before any treatments
      Dr D

  2. yolanda on May 5, 2011 at 10:05 pm

    Dr Dressler
    I have searched your book, on enlarged liver cancer,
    I am confused, could you please tell me what is the best treatment for liver, well I have k9, curcumin, krill oil dr.goodpet enzimes, silymarin,,teavigo, looks like teavigo not recommend for liver ,well normally i give him k9, krill oil. and silymarin,but he is not immproving, my dog is 11 years old
    Thank you

    • DemianDressler on May 18, 2011 at 9:18 pm

      Dear Yolanda
      I am sorry to hear about this problem with your dog.
      In order for us to give you the information, we need to know the kind of cancer. Many cancers can happen in the liver. Without this info, it is hard to recommend chemo or the kind of drugs to use, whether surgery is an idea, diet changes, and so on.
      Can you find this out?
      Dr D

  3. Trina on May 1, 2011 at 11:22 am

    Dr. Dressler,

    I have searched your book and site and can only find this one mention of bladder stones & cancer. My dog has had calcium oxalate uroliths removed, along with an anal gland carcinoma. (Not to mention the leg amputation for the Grade 2 soft tissue sarcoma on his hind leg.) I was told to feed him Hills U/D but am reluctant because I haven’t read good things about it’s ingredients. I want to feed my dog your suggested Full Spectrum diet but don’t know what foods I should leave out, or add. Are you able to help me? Thanks for your time.

  4. Rae on June 1, 2010 at 7:56 am

    Dr. Dressler:
    Thank you so much for your response and the additional suggested reading. It all makes sense now, (at least the distinctions and mechanism of action). However, I still don’t know if any of the substances that stimulate the immune system are considered anti-oxidants (e.g. fish oil, arginine, K-9 Immunity & Transfer Factors)? Are any of these supplements likely to affect free radicals created by cyclophosphamide or arteminisin, and thus decrease their effectiveness? Also, the one link to “New Antioxidant Info…” mentions that to maximize the killing effects of chemo, wait 2 weeks after the last pill is given. My dog is on daily oral cyclophosphamide, so essentially there is no “last pill” during treatment. I no longer have revised diet in my arsenal, as my dog has just begun to lose her appetite for the first time in her life. Do you recommend only Artemisinin, or the derivatives as well? Are apocaps an antioxidant, pro-oxidant, or neither? I am sort of on my own here, as my oncologist is VERY allopathic. Beatty’s prognosis at this point is very grim, and I am trying to devise a treatment plan for the best possible chance of her survival. X-rays are scheduled for next week to see if the tumors are growing on the new protocol. This is what I have been doing…(75 lb dog)
    10 mg cyclophosphamide daily
    400 mg doxycycline daily
    100 mg previcox daily
    fish oil
    200 mg artemisinin 5 days on, 5 days off
    planning to start K-9 Immunity and arginine on the “off” days?
    Thank you so much for your time, and for the invaluable support and hope that you provide for guardians of dogs with cancer.

    • Dr. Dressler on June 6, 2010 at 11:18 pm

      Dear Rae,
      the question is too involved to answer in this forum as there are too many factors to explain. No, immune stimulation does not necessarily go hand in hand with antioxidant effects. Are “antioxidants” always bad with chemo? Grouping items together based on the fact that they have antioxidant effects truly is problematic (since the effects of different substances with antioxidant traits are totally different from each other and are totally different than they are in the test tube).
      Have you read the Dog Cancer Survival Guide?
      If the veterinary care you are receiving now is too restricted in scope, this would motivate most to get another vet involved. You need someone to help your individual dog with the unique needs present.
      Chemo drugs do not only kill cells by increasing free radicals, they have other mechanisms too, fyi…
      Apocaps net effect is pro oxidant. Art’s net effect is pro oxidant. fish oil, TF, and K9 Imm are antiox, arg is neither, but the net effects are likely benefical in spite of the free radical issue since they do other things (immune support and more..)
      I would pulse 5 days apocaps, 5 days art alternating with apocaps, and give the others at least 4 hours apart from art or apocaps daily. All of this should be under veterinary supervision.

      Dr D

  5. Rae on May 21, 2010 at 7:32 am

    Dr. Dressler:
    Help! My dog has axial osteosarcoma of the rib. Surgery was done to remove the tumor 9 wks ago, and we got through only 2 chemo treatments before finding out this week that the tumor is growing back and there is a 1cm lung nodule which was not there 4 wks ago. Treatment was changed to daily oral chemo (palladia alternating with cyclophosphamide), daily doxycycline and previcox. I was cautioned to stop any antioxidants. I have been supplementing with arginine and fish oil…are these antioxidants? Just a few days ago I ordered Artemisinin and K9 Immunity as well. Since K9 Immunity contains cordyceps do I have to use it only on the “off” days of arteminisin, or is that as bad as using them together? Should nothing that stimulates the immune system be used with chemo? Are all substances that stimulate the immune system considered antioxidants? I am confused, desperate, and running out of time while I exhaustively research this topic. Can you shed some light? I know she doesn’t have long no matter what I do, but I’d like to know that I’m doing isn’t counterproductive; I feel like throwing everything possible at this cancer, but I’m learning that this may make nothing work as its supposed to! Clinically she seems absolutely fine and healthy…I’d like to keep her that way for as long as possible.
    Thank you!

    • Dr. Dressler on May 22, 2010 at 4:47 pm

      Dear Rae,
      I am sorry to hear this news. The question of anti oxidant use is one that has not received the attention that it deserves in conventional medical circles. Please read these posts:
      What we have here is support for a certain type of cancer therapy (the conventional allopathic approach). I lean towards combination approaches in medicine personally if one approach is not alleviating the problem to an acceptable level.
      The bottom line is this: if the cancer is regrowing while on the protocol the dog is on, it may be wise to shift gears (i.e. change plans), of course under supervision of your veterinarian. There are many approaches to managing cancer, and if one is not working, it may worth considering new approaches. You may want to investigate the use of Apocaps to help support normal life quality and expectancy as well.
      Write back after you have had a chance to digest this information and perhaps had more consultation with your veterinary team.
      Dr D

  6. wisam on December 29, 2009 at 6:54 am

    Hello Dr.
    I’ve got a dog very sick and I do not know what to do with glaze went to 4 veterinary doctor did not give me a clear result and I hope that you never help me with advice
    Dog-type Rottweiler and overhaul two years and three months, suddenly does not want to eat after 7 days was the lack of talents from 64 to 30 kilograms and now his eyes were purple happened two days after swelling in the abdomen, where he became like a pregnant female can not move and never distract him Dr. needle every 2 on a penicillin and vitamin C for 5 days was not the result we come please help me I’m never knowing that the medicine the human form in Libya is very bearish, what about veterinary medicine please help me

    • Dr. Dressler on December 30, 2009 at 12:18 pm

      Dear Wisam
      I am sorry but there could be many different things wrong- abdominal swelling could be from heart failure, tumor, kidney or liver disease, and many other things. We need more information here. No ultrasound available?
      Dr D

  7. Nora on December 28, 2009 at 6:27 am

    Dr. Dressler,

    I have a 7 years old German Boxer, who was diagnosed with ” Suspected epitheliotrophic malignant lymephoma” as written on his report after biopsy. At first most of the Vets told me its an ulcer, then after biosy i had this diagnosis. Its on his upper left lip, a huge open wound. I bought your book and i applied some of your procedure. Iam located in Kuwait , but there is no good Vets here. They gave me 6 month for my Boxer to live. He had this for a whole year before biospy and never had any other symptoms up until now. I gave him K-9 immunity also, now iam giving him PAW PAW cell reg, i read about it online. Now i would like to add the IV VIT. C, but Dr. Dressler what is the dosage? and how many times .. daily or once a week etc?

    The Vets here told me no use for chemo, they totally gave up on my dog,and he is acting totally fine , no symptoms for over a year now. so everything iam doing is from my own reading, no vet will do anything here. You have been a great help, thank you so much.

    • Dr. Dressler on December 30, 2009 at 12:12 pm

      Dear Nora,
      There are no published protocols for this use in dogs, so we have to modify what has been done in humans. Your vet can help with that. Here is an excerpt from the link in the blog post used for a human:
      “The patient declined chemotherapy and radiotherapy, opting instead for 30 grams of vitamin C twice a week for three months, followed by 30 grams once every one to two months for four years, interspersed with periods during which he had more frequent infusions.”
      I hope this helps,
      Dr D

  8. Fred on December 18, 2009 at 5:15 am

    Dr. Dressler,

    I would like to comment about the IV use of vitamin C. You call ascorbic acid vitamin C. I do not believe that ascorbic acid is vitamin C and the reason for that belief was placed in my mind by an article by Dr. Szent-Gy ö rgyi (the discoverer of vitamin C) in a monthly publication named “Executive Health” which I kept for years, but it disappeared some time ago, but not the thought that Dr. Szent-Gy ö rgyi put there.
    Dr. Szent-Gy ö rgyi was called in to treat the Crown Prince of Belgium for subcutaneous bleeding. Dr. Szent-Gy ö rgyi believed the Prince had a vitamin deficiency, but could not understand why since he had available the best chefs and food sources. Dr. Szent-Gy ö rgyi treated the Prince and the condition with his extracted (ascorbic acid) was resolved. Not long after that, he was called in to treat another man with the same condition. The ascorbic acid did not resolve the problem. Dr. Szent-Gy ö rgyi then went back to his original vitamin C source which he had extracted from Paprika and the problem was resolved. Dr. Szent-Gy ö rgyi concluded that there must be trace “food factors” in the “raw” vitamin C which were not in ascorbic acid. These trace markers vary with the source (Acerola Cherry has one of the highest concentrations of vitamin C) and is highly touted in most all vitamin C supplements sold. However, Chemists at the largest manufacturer of vitamin C from Acerola Cherry (owning 90% + of all the sources in the world) does not find those trace food factors in vitamin C claiming to be derived from Acerola Cherries).

    I hope that any IV preparations supplied are real vitamin C and not ascorbic acid.

    Dr. Szent-Gy ö rgyi approached Merck & Co. with his discovery of vitamin C. The Merck question to Dr. Szent-Gy ö rgyi was, “what does you vitamin C cure”? Dr. Szent-Gy ö rgyi replied, scurvy. Merck responded, “we have no scurvy, therefore we have no need for your vitamin C.” I believe that goats produce ~140,000mg of vitamin C daily. Humans produce none.

    Remember that it took the Brits 90 years to discovery the cure for beriberi!


  9. John on December 17, 2009 at 12:41 pm

    My 11 year old has SCC in her lower jaw we have done radiation and chemo therapies. What are other modes of treatments and do you think the vitamin C IV would work.

    • Dr. Dressler on December 22, 2009 at 9:44 pm

      Dear John
      I am sorry to say that the studies have not been done to answer your question with any certainty. It is not likely to hurt once the radiation and chemo is complete, but I would give some time between them to be on the safe side, very roughly about 2 months as a rough estimate. As far as other things that can be done, one could fill a book…which I did with the e-book…. 🙂
      Diet, life quality, sunlight, supplements, etc. all can give an edge.
      Dr D

  10. jennifer on December 17, 2009 at 6:48 am

    I have a Beagle who is having her final chemo treatment in Jan. and will go into her first remission. What are your thoughts on using Vitamin C as a preventative measure? It is likely that we will not opt for a second round of treatment for her–she is a very anxious girl (due to previous abuse) and chemo was stressful for her.

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