- Overdose damages the kidneys
- 12–36 h
- Affects: Kidneys (calcium)
Why this verdict for dogs
Vitamin D overdose — from supplements, some rodenticides, or psoriasis creams — raises calcium to dangerous levels and damages the kidneys. The effect builds over days.
Warning signs to watch for
- Increased thirst & urination
- Vomiting
- Loss of appetite
- Weakness
⚠ If your dog ate vitamin d supplements
Act immediately — don't wait for symptoms.
- Call your vet or a pet poison helpline right away.
- Note how much was eaten and when.
- Do not induce vomiting unless a professional tells you to.
Vitamin D is the poison that hides inside things labelled healthy. It reaches pets through supplement bottles, some psoriasis creams, cholecalciferol rodent bait, and — in a string of well-publicised recalls — pet food where a manufacturing error put far too much of it in the bag.
How much is safe?
Vitamin D is fat-soluble, so it accumulates rather than being flushed out, and the margin is narrow. Toxicity in dogs can begin around 0.1 mg/kg of cholecalciferol, and it is measured in micrograms, which makes label reading essential. Human supplements are often dosed in the thousands of IU, so a chewed bottle is a large exposure. Topical psoriasis creams containing calcipotriene are especially concentrated, and a dog licking a treated arm or chewing the tube is a documented emergency.
What happens if a dog eats too much?
Excess vitamin D drives calcium out of the bones and into the blood, and that calcium then mineralises the kidneys, heart and blood vessels — damage that is difficult to reverse. The first signs, appearing over one to three days, are increased thirst and urination, vomiting, appetite loss, weakness and constipation. Kidney failure follows. Because the early picture looks like a routine upset stomach, it is frequently under-reacted to.
⚠ What to do if your dog ate vitamin d supplements
Call your vet or a poison line with the exact product and strength in IU or micrograms (ASPCA 888-426-4435 · Pet Poison Helpline 855-764-7661). This is one where blood calcium needs monitoring for several days even if your pet seems fine, because the damage is silent early and hard to undo once mineralisation begins. Early decontamination and fluids make a substantial difference.
⚠️ Worried your pet got into this?
Frequently asked questions
My dog licked my psoriasis cream — is that really dangerous?
Yes, and it is one of the most serious vitamin D exposures vets see. Calcipotriene is highly concentrated. Call immediately.
What about vitamin D in dog food?
Correctly formulated food is fine — dogs need vitamin D. The risk comes from manufacturing errors, which is why checking recall notices for your brand is worth doing.
More medications for dogs
By the CanMyPet Editorial Team · Reviewed against ASPCA Animal Poison Control, the American Kennel Club (AKC) and Pet Poison Helpline · Last updated July 31, 2026.
Sources
- ASPCA — People Foods to Avoid Feeding Your Pets
- American Kennel Club — Dog Nutrition
- Pet Poison Helpline — Poison List