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

Could Killing “Good” Bacteria Increase GI Cancer Risk?

Updated: March 19th, 2019

Could destroying the normal bacteria in your dog’s body be a risk factor for cancer down the road?

This may sound very far-fetched.  However, in the spirit of avoiding condemnation before investigation, read on!

It turns out that the so-called “healthy” bacteria in the body may provide cancer protection.  And therefore, if this bacteria is destroyed with antibiotics and replaced with “unhealthy” bacteria, does it follow that there is a cancer risk?

Let’s first look at the natural bacteria found in bodies.  These live mainly in the GI tract, but are also located on the skin and in body cavities.  Healthy intestinal bacteria vary between species, but can include bacteria like  some strains of lactobacillus, bifidobacteria, strept, and others.

These bacteria are beneficial as they help block disease causing microbes, help stimulate immunity, and help provide the body with vitamins.

However, what happens when these bacteria are destroyed?  Or, are never received by the newborn, such as during a Cesarian section surgery (beneficial bacteria are transferred to the newborn in mom’s reproductive tract).

The frequent result is that the intestine is colonized with bacteria that are not especially healthy, such as some strains of clostridia and bacterioides.  These do not provide the benefits of the healthy bacteria, and there is some research that they may produce toxic waste products that create inflammation and precancerous changes in the intestine of lab animals and humans.

Additionally, helicobacter is a risk factor for stomach inflammation and pre-cancerous changes, as opposed to the intestine.  This is another example of an “unhealthy’ bacteria.

Although there is not a direct cause and effect yet established in pets or people for many of these changes, I believe we will be seeing much more data on this over the next decade.

Meanwhile, discuss with your vet the use of a couple of weeks of a high quality probiotics after longer term (3-7 days’) antibiotic use.  Probiotics are healthy bacteria supplements.

Make sure this healthy bacteria supplement is protected from the stomach acid and enzymes so it can reach the lower part of the intestine without being destroyed in the stomach.  There are different quality probiotics.

I feel that lower potency sources such as organic yogurt may not be entirely adequate.  Finally, you may provide the fuel for these bacteria, which are called prebiotics.  One common one is inulin.

Healthy dogs requiring probiotics and prebiotics benefit from the new product Everpup.


Dr D



Discover the Full Spectrum Approach to Dog Cancer

Leave a Comment

  1. Ed Capps on November 15, 2012 at 4:03 am

    Dr D,

    I have been reading about mushrooms being very beneficial for gut flora, and some such as Reishi mushrooms even show some evidence for bringing about apoptosis. I am going to start taking them myself, and wondered if they are safe for dogs.

    Thank you

    • Dr. Demian Dressler on November 27, 2012 at 12:00 pm

      Dear Ed,
      this is discussed at length in the Guide, which is a good read for anyone interested in topics like this. I would suggest a veterinary supplement for beta glucans like k-9 immunity or similar.
      The other thing you could do is check out everpup, which has some beta glucans and a whole slew of other beneficial ingredients for cellular protection.
      Dr D

  2. steve on June 6, 2012 at 12:50 pm

    dear dr. dressler, My dog max, a boston terrior, died suddenly of hemangiosarcoma in his heart. He was 11years old. He had chronic glaucoma and was blindin that eye but he was not in any pain which was controled by the eye drops. His eye pressure was normal. How ever I was wondering what could have caused this cancer that ended his life. I loved him more than anyone in my life and still am in some shock about his death which was back in october. thanks

  3. Garry Sheen on June 6, 2012 at 4:20 am

    It’s really great to hear that Kayla is doing so well:) Our Logan was diagnosed with TCC at the beginning of May. Unfortunately, the tumour isn’t operable, but he is receiving chemo and the supps he is on broadly reflect Kayla’s (we’re hoping for him to be on Apocaps soon). We’re having great problems getting him to eat (I give each of the supps with a little pork liver treat just before we attempt a meal!) even though it’s almost 3 weeks since his last chemo session.
    Apart from wishing you and Kayla all the very best, Margaret, I’d also be interested in hearing what Dr D has to say re. EverPup for dogs with cancer.
    Warm regards
    Garry (UK)

  4. Margaret (& Kayla) on June 1, 2012 at 10:30 pm

    Hi Dr. Dressler,

    My dog, Kayla, (and I) are dealing with a recent diagnosis of TCC. She has had a successful surgery to remove cancerous tissue from her bladder (4 week post-surgery ultrasound this week looks great and there is thus far no lymph node involvement). She is a 23 lb. 9-year old schipperke/papillion/border collie mix (best guess of our vet, as I adopted her at 6 months of age from a shelter). She has been on your dog cancer diet for 6 weeks with K-9 Immunity, Transfer Factor, digestive enzymes, Apocaps (1/2 dose), and Metacam. Daily Cipro (morning) was added this week along with a high quality probiotic (evening), and I started her on modified citrus pectin this week as well. She is eating, drinking, peeing(!), playing, and sleeping very well (I live in Fairbanks, Alaska, and have created a dark den for her to sleep in despite our current midnight sun). My question is, will she benefit from the addition of EverPup, or is it contraindicated with her current cancer and related treatment(s)?

    Kind regards,
    Margaret & Kayla

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