Grape & Raisin Toxicity Calculator for Dogs
Dog ate grapes or raisins? Enter your dog's weight and the type and amount consumed to get an instant toxicity risk assessment.
What happened?
Important: Grape toxicity is unpredictable
Approximately 73.9% of dogs that ingest grapes remain asymptomatic (Downs et al. 2024), but there is no way to predict which dogs will develop kidney failure. Tartaric acid concentration in grapes varies from 0.35% to 2.0% depending on variety, growing conditions, and ripeness. Dogs lack the OAT4 transporter that humans use to excrete tartaric acid, making them uniquely vulnerable.
While the estimated dose is below commonly cited thresholds, there is no established safe dose for grapes or raisins in dogs. Some dogs have developed acute kidney injury from as few as 4–5 grapes. Contact your veterinarian for guidance and monitor your dog closely for 72 hours.
ℹ️ Merck Veterinary Manual rule of thumb: More than 1 grape or raisin per 10 lb (4.5 kg) of body weight may pose renal risk. Your dog ate 5 fresh grapes, exceeding the threshold of 3 for a 30 lbs dog.
Dose breakdown
☎️ Emergency contacts
How we calculated this
5 pieces × 5 g each = 25.0 g
Average weight per fresh grapes (Cortinovis & Caloni 2016)
25.0 g ÷ 13.6 kg = 1.84 g/kg
1.84 g/kg consumed vs. 20 g/kg reported threshold
Lowest reported toxic dose: 20 g/kg for fresh grapes (Cortinovis & Caloni 2016). There is no confirmed safe dose for any dog.
How Grapes Affect Dogs
The toxic compound in grapes is tartaric acid, as first proposed by Wegenast et al. in 2021. This was confirmed by subsequent research showing that cream of tartar (potassium bitartrate) and tamarinds — both high in tartaric acid — cause the same acute kidney injury pattern in dogs.
Dogs are uniquely vulnerable because they lack sufficient expression of the OAT4 transporter in their kidneys. Humans use this transporter to efficiently excrete organic acids like tartaric acid. Without it, tartaric acid accumulates in the proximal renal tubular cells, causing direct cellular damage and acute kidney injury.
Critically, tartaric acid concentration in grapes varies dramatically — from 0.35% to 2.0% — depending on grape variety, growing region, climate, and ripeness at harvest. This is why grape toxicity appears so unpredictable: the same number of grapes from different batches can deliver vastly different doses of tartaric acid.
Symptoms Timeline
0–12 hours: Early signs
The most common early symptom is vomiting, typically appearing within 6–12 hours of ingestion. Diarrhea, lethargy, loss of appetite, and abdominal pain may also develop during this window. Vomiting can be protective, as it may reduce the amount of tartaric acid absorbed.
12–24 hours: Monitoring phase
During this period, kidney damage may be developing even if your dog appears stable. Early blood work can appear normal, which is why repeat testing is important. Decreased urination is a particularly concerning sign that may indicate developing renal injury.
24–72 hours: Kidney failure risk
Oliguric or anuric renal failure (reduced or absent urine production) typically develops in this window. Lab findings may include elevated BUN and creatinine, hyperphosphatemia (90% of cases), and hypercalcemia (62% of cases). Once anuric renal failure develops, the prognosis becomes very poor — the Eubig et al. (2005) retrospective found a 47% mortality rate among dogs that developed acute kidney injury.
What to Do If Your Dog Ate Grapes
Step 1: Stay calm and assess the situation
Identify what your dog ate (grapes, raisins, sultanas, currants, or a food product containing them). Try to estimate the amount consumed. Note the time of ingestion.
Step 2: Contact your veterinarian immediately
Do not wait for symptoms. Call your vet, an emergency veterinary clinic, or the Pet Poison Helpline at (855) 764-7661. Provide the type and estimated amount consumed, your dog’s weight, and the time of ingestion.
Step 3: Decontamination (if within 2 hours)
If ingestion occurred within the last 1–2 hours, your vet may induce vomiting to remove undigested material, followed by activated charcoal to reduce further absorption. Do NOT induce vomiting without veterinary guidance — it can be dangerous in some situations.
Step 4: Veterinary monitoring
Your vet will likely recommend IV fluid therapy for at least 48 hours to support kidney function and promote excretion. Blood work (BUN, creatinine, phosphorus, calcium) should be monitored over 2–3 days, as early values may appear normal even if injury is developing.
Which Grape Products Are Most Dangerous?
Not all grape products carry equal risk. Here is a ranked list from most dangerous to least, based on tartaric acid concentration:
- Cream of tartar — Pure potassium bitartrate (a salt of tartaric acid). Any measurable amount is a veterinary emergency.
- Raisins, sultanas, and currants — Dehydration removes water but concentrates tartaric acid. Approximately 4–5× more concentrated than fresh grapes by weight. Commonly cited threshold: ~3 g/kg body weight.
- Fresh grapes (all varieties) — Red, green, seeded, seedless, commercial, and homegrown. Commonly cited threshold: ~20 g/kg body weight, but cases of AKI from as few as 4–5 grapes have been documented.
Products NOT associated with grape toxicosis
Grape juice, grape jelly, grape seed oil, and wine have NOT been associated with the same toxicity pattern. Processing likely removes or breaks down tartaric acid. However, wine and other alcoholic beverages pose their own separate toxicity risks to dogs.
Sources & References
- Gwaltney-Brant SM, Holding JK, Donaldson CW, et al. Renal failure associated with ingestion of grapes or raisins in dogs. JAVMA. 2001;218(10):1555–1556. First published report linking grape/raisin ingestion to acute renal failure in dogs.
- Eubig PA, Brady MS, Gwaltney-Brant SM, et al. Acute renal failure in dogs after the ingestion of grapes or raisins: a retrospective evaluation of 43 dogs (1992–2002). JVIM. 2005;19(5):663–674. 47% mortality rate in dogs that developed AKI.
- Wegenast C, Meadows I, Anderson R, Southard T. Unique sensitivity of dogs to tartaric acid and implications for toxicity of grapes. JAVMA. 2021;258(7):704–707. First to propose tartaric acid as the toxic principle.
- Wegenast CA, Meadows ID, Anderson RE, et al. Acute kidney injury in dogs following ingestion of cream of tartar and tamarinds. JVECC. 2022;32(6):812–816. Confirmed tartaric acid as common toxic principle.
- Coyne SR, Landry GM. Tartaric acid induces toxicity in Madin–Darby canine kidney cells. JVECC. 2023;33(3):298–304. OAT transporter mechanism in canine kidney cells.
- Reich CF, Salcedo MC, Koenigshof AM, et al. Retrospective evaluation of grape or raisin ingestion in dogs (2005–2014): 139 cases. JVECC. 2020;30(1):60–65. 6.7% AKI prevalence; decontamination improves outcomes.
- Downs J, Zoltowska A, Hackney T, et al. Scoping review of Vitis vinifera toxicity in dogs. Veterinary Record. 2024;195(7):e4536. 1,163 dogs reviewed; 73.9% asymptomatic; no dose-response relationship.
- Cortinovis C, Caloni F. Household food items toxic to dogs and cats. Frontiers in Veterinary Science. 2016;3:26. Source for commonly cited thresholds (~20 g/kg grapes, ~3 g/kg raisins).
- Cornell University CVM — Riney Canine Health Center. Grape and raisin toxicity. Updated December 2025.
- Merck Veterinary Manual — Grape, Raisin, and Tamarind Toxicosis in Dogs. Updated 2024. Clinical threshold: >1 grape per 10 lb body weight.
- VCA Animal Hospitals — Grape, Raisin, and Currant Poisoning in Dogs. Diagnosis and treatment guidance.
- Clinician's Brief — Tartaric acid and raisin poisoning in dogs: Study takeaways.
- Craft E, Lee JA. Grapes and raisins. In: Osweiler G, et al., eds. Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Toxicology. 1st ed. Wiley-Blackwell; 2010:429–435.
Disclaimer: This calculator provides risk estimates based on published veterinary data and commonly cited toxicity thresholds. There is no established safe dose for grapes, raisins, or related products in dogs. Actual tartaric acid content varies significantly between grape varieties, growing conditions, and processing methods. This tool is not a substitute for professional veterinary advice. When in doubt, always contact your veterinarian or the Pet Poison Helpline at (855) 764-7661.
Frequently asked questions about grape and raisin toxicity in dogs
Can a single grape kill a dog?
While a single grape is unlikely to kill most dogs, there is documented evidence of acute kidney injury from as few as 4–5 grapes in a small dog (Downs et al. 2024). The toxic principle — tartaric acid — varies widely between grape varieties, growing regions, and ripeness levels. Because there is no established safe dose, even a single grape warrants monitoring and a call to your vet, especially for small dogs.
Why are grapes toxic to dogs but not humans?
The leading hypothesis is that tartaric acid is the toxic compound in grapes (Wegenast et al. 2021). Dogs lack sufficient expression of the OAT4 transporter in their kidneys, which humans use to efficiently excrete organic acids like tartaric acid. Without this transporter, tartaric acid accumulates in the proximal renal tubular cells, causing direct cellular damage. This was confirmed in vitro by Coyne & Landry (2023), who showed tartaric acid is toxic to canine kidney cells but not human kidney cells.
Are raisins more dangerous than grapes?
Yes. Raisins, sultanas, and currants are 4–5 times more concentrated than fresh grapes by weight because dehydration removes water but concentrates the tartaric acid. The commonly cited toxicity threshold for raisins is approximately 3 g/kg body weight, compared to 20 g/kg for fresh grapes (Cortinovis & Caloni 2016). A small box of raisins contains significantly more tartaric acid than an equivalent weight of fresh grapes.
Is grape juice or wine toxic to dogs?
Grape juice, grape jelly, grape seed oil, and wine have NOT been associated with the same toxicity as whole grapes and raisins (Cornell University CVM; Wegenast et al. 2022). Processing likely removes or breaks down the tartaric acid. However, wine and other alcoholic beverages pose their own separate toxicity risks to dogs. When in doubt, consult your veterinarian.
What about cream of tartar?
Cream of tartar (potassium bitartrate) is essentially a purified salt of tartaric acid — the very compound believed to cause grape toxicity. Dogs that ingested cream of tartar developed acute kidney injury with the same clinical presentation as grape toxicosis (Wegenast et al. 2022). Even small amounts of cream of tartar should be treated as a veterinary emergency.
What are the symptoms of grape poisoning in dogs?
Early symptoms (within 6–12 hours) typically include vomiting, diarrhea, lethargy, and loss of appetite. More concerning signs that may develop over 24–72 hours include decreased or absent urination (oliguria/anuria), abdominal pain, dehydration, and tremors. Once anuric renal failure develops, the prognosis becomes very poor. The Eubig et al. (2005) retrospective found a 47% mortality rate among dogs that developed acute kidney injury.
How long after eating grapes will a dog get sick?
Vomiting and diarrhea typically appear within 6–12 hours of ingestion. Kidney damage develops over 24–72 hours. However, early blood work may appear normal even if kidney injury is developing, which is why veterinarians recommend repeat testing over 2–3 days (VCA Animal Hospitals). Some dogs may not show obvious symptoms until significant kidney damage has occurred.
What will the vet do if my dog ate grapes?
Treatment depends on timing and severity. If within 1–2 hours, your vet will likely induce vomiting to remove undigested material, followed by activated charcoal to reduce further absorption. IV fluid therapy (typically for 48+ hours) is the cornerstone of treatment to protect kidney function. Blood work (BUN, creatinine, phosphorus, calcium) will be monitored over 2–3 days. In severe cases with anuric renal failure, hemodialysis may be considered (Merck Veterinary Manual; VCA Animal Hospitals).
My dog ate grapes before and was fine. Is it safe?
No. The Downs et al. (2024) scoping review found that approximately 73.9% of dogs that ingested grapes remained asymptomatic. But this does NOT mean it is safe. Tartaric acid concentration varies dramatically (0.35%–2.0%) between grape varieties, growing conditions, and ripeness levels (Wegenast et al. 2021). A grape variety your dog tolerated once could be far more concentrated the next time. There is no way to predict which exposure will cause kidney failure.