Pets Poisoned by Vitamin!

I recently saw a safety alert issued by the ASPCA on a new form of pet poisoning that is affecting dogs and cats in record numbers.  Alarmed, I decided to dig deeper into the new rat-poisons that are on the market that are causing this problem.  Weirdly, it appeared to be an overdose of Vitamin D.  Thinking this could not possibly be true, I continued on. Sure enough, it’s true and this is what I found.

From the ASPCA…

“ Animal Poison Control Center received only a small number of calls involving cholecalciferol rodenticides. Unfortunately, that is no longer the case. A popular manufacturer of rodenticides is now producing a bait with cholecalciferol and so far this year the APCC has seen a nearly 2000 percent increase in calls involving cholecalciferol rodenticides. “

A 2000 % increase for 2018 in any kind of poisoning is horrific.  What is this toxin and who is distributing it?

Cholecalciferol is a fancy name for Vitamin D3. How on earth can a substance critical for life processes in humans, dogs, and cats be toxic?  It turns out it’s all a matter of quantity. Vitamin D plays an essential role in the regulation of calcium and phosphorus metabolism :

  • increase in the intestinal absorption of calcium and phosphorus;
  • optimization of calcium bonding (or unbonding) of bone  tissue;
  • reduction in the loss of calcium and phosphorus in the urine.

Vitamin D deficiency can cause rickets (used to be rare in dogs and cats but is on the rise) also called osteomalacia (joint and muscle pains, bone fractures), possibly certain forms of cancer and immune deficiency, congestive heart failure, neoplasia, kidney disease, infectious illnesses, irritable bowels, and feline oral resorptive lesions (FORL).

Too little Vitamin D can shorten your pet’s life span. See, dogs and cats cannot synthesize D from exposure to sunlight as effectively as humans, and have evolved to acquire this nutrient through consumption of fatty meats and liver. Vitamin D3 is first absorbed through the intestines, then converted in the liver to 25-hydroxyvitamin D (or 25VitD). This active form of vitamin D that the body can utilize, also called calcitriol. Ironically, most dry pet foods don’t contain enough, although some contain huge amounts. In fact, in 2010, Blue Buffalo had to recall all chicken based kibble from a particular lot that had given dogs mild D3 poisoning (all dogs returned to normal after a change in diet according to an article by the American Veterinary Medicine Association).

So what happens with too much? Turns out this same nutrient can destroy the very life processes that it assists with when ingested in excessive amounts.  Here is what the Pet Poison Helpline has to say about the new rodenticides whose active ingredient is cholecalciferol.

“Cholecalciferol, or activated vitamin D3, causes life-threateningly high calcium and phosphorus levels in the body, resulting in severe, acute kidney failure. This can progress to chronic kidney failure and have long-term repercussions. Common signs of poisoning may not be evident for 1-2 days, when the poison has already resulted in significant -and potentially permanent – damage to the body.”

Unfortunately, cholecalciferol mouse and rat poison does not have an antidote and is one of the most challenging poisoning cases to treat since hospitalization, frequent laboratory monitoring of calcium, phosphorus, and kidney values for several weeks and expensive therapy is often required for a positive outcome. Treatment includes continual IV fluid administration for up to 3 days along with drugs such as diuretics, steroids, calcitonin, and bisphosphonates required for decreasing calcium levels in the body.

Expensive for the owner and unpleasant for the victim, with full healing and recovery for all of the affected organs not guaranteed.  And there is no antidote!  Unlike the anti-coagulant rat poisons of yore, and there are still a few out there, this form of poisoning cannot be negated by immediate administration of Vitamin K.  For this reason, the main producer of this new rodenticide has produced an educational webinar to inform the public and veterinarians on the symptoms of this poisoning and what needs to be done.  Essentially, the victim needs a system flush. Ironically, this manufacturer developed this product in response to a 2011 EPA mandate concerning the elimination of a whole category of anti-coagulants that were pretty dangerous to children and pets but DID have an anti-dote.

If you believe your pet may have ingested this product or another one with activated D3 as the main lethal ingredient, try to take the packaging with you to the vet (and you will need to go to the vet).  If the packaging is not available, take note of all of your pet’s symptoms which may be:

Bad breath

Bloody feces



Excessive or unusual salivation

Excessive or decreased thirst

Increased or decreased urination

Loss of appetite




Vomiting (sometimes with blood)

Weakness or lethargy

These symptoms may help in rapid diagnosis when the toxin is unknown. Unfortunately, symptom onset can be up to 2 days after ingestion, so immediate care by a professional is called for.

There are several ‘people’ vitamins that contain plenty of vitamin D, including multivitamins and omega fatty acid supplements. Be aware that even a small, harmless dosage of vitamin D intended for humans can cause cholecalciferol poisoning in dogs. In fact, it only takes one milligram per pound of body weight to cause symptoms, and it can be fatal at just four milligrams per pound of body weight. That means just one multivitamin, which contains an average of 25 milligrams of vitamin D, can be fatal for a 5-pound dog. So in addition to securing all rodenticides in a really inaccessible place, multivitamin supplements should never be administered to pets and disposed of in pet-safe trash receptacles if being discarded as expired. Also, be warned that the new bait by d-Con looks like a green, soft, chewable, wrapped candy, which might be very attractive to pets and children.  The product comes initially in a pet-proof plastic trap, but the refills do not and these seem to be the source of the current epidemic. This product or anything like it should really be kept under lock and key and not under the kitchen sink.

I hope this post is useful to pet parents and maybe even saves some lives.  For more information you can contact the Pet Poison Helpline or the ASPCA Animal Poison Control Center at (888) 426-4435.

If you are wondering about dog foods in general, I took the time to research Blue Buffalo.  Although they still include D3 supplementation, they are highly rated by  Dog Food Advisor-reviews.

The ingredients look really top notch in general, although the reviewers do not like the addition of good color, so the product was rated at 4 out of 5 on that score.  I liked the fact that they do include taurine, essential for heart health in dogs (see this blog on taurine deficiency). So this looks like an excellent and affordable product in general, just be sure that if you are providing this or any product with D to your dog you do not also supplement him or her with a pet multivitamin containing any D supplementation and be aware that if your dog gets into rodenticides containing D that the toxic effects may be compounded.


  1. Thank you for this information. Have a question as we have had more than our fair share of mice this summer and fall. Do you have a good pet safe solution to get rid of mice?

  2. I have heard very good things about sonic repellents. I have not personally tried them but I know people who have done so and they have about a 60% success with this. I think it may depend upon the dimensions of the house and whether or not there is a basement. I do have experience with a massive rodent infestation in a barn that was of plaguelike proportions one year, and then almost gone the next after a hard winter and a new, aggressive barn cat took up residence. The old barn cat was very spoiled and fed a wholesome diet of Science Diet Senior Cat formula, and very happy with her lot in life, which did not include catching mice. When the new, young and univited feral cat moved in during a hard winter, the mouse populaton crashed. If you live in a suburban area in a warm climate such as San Diego, where I used to live, I would absolutely recommend that you research and then choose a sonic product. I can tell you that after a mild winter in Utah, I trapped more than 10 mice a week for at least 10 weeks. It was not pretty, and so a repellent sound that actually does the job would be way better. Hope this was helpful.

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