Call ASPCA Poison Control: (888) 426-4435 or go to your nearest emergency vet. Do not wait for symptoms to appear.
Grapes, raisins, currants, and sultanas are all toxic to dogs. The exact toxic compound is still unknown, making every ingestion unpredictable — some dogs develop life-threatening kidney failure from a few grapes while others show no symptoms. Because there is no established safe dose, all ingestion must be treated as an emergency.
Border Collies carry the MDR1 (ABCB1) gene mutation at higher rates than most breeds, which impairs the blood-brain barrier's ability to exclude certain drugs and toxins. This means some substances — including common antiparasitic medications and certain sedatives used in treatment — can cause severe neurological toxicity in Border Collies even at doses safe for other breeds. This gene mutation is critical to disclose to your vet.
Why Does Breed Matter for Grapes Toxicity?
Toxic doses for grapes are calculated per kilogram of body weight. A Border Collie typically weighs 12–20 kg, which directly determines how much an unknown nephrotoxic compound their body is exposed to relative to their size. Beyond weight, Border Collies have specific traits — outlined in the breed profile above — that can affect how quickly symptoms develop, how severe they become, and what complications to watch for.
When you call Poison Control, always give your dog's exact current weight, not a breed average. Even within the Border Collie breed, a significant weight difference changes the risk calculation meaningfully.
How Much Grapes Is Toxic to a Border Collie?
These thresholds are based on the typical Border Collie weight range of 12–20 kg. Always use your dog's actual weight for the most accurate estimate. Use our Grape Toxicity calculator to enter your dog's exact weight.
| Dog weight | Mild signs | Serious signs | Potentially fatal |
|---|---|---|---|
| 12 kg (small Border Collie) | No safe dose — any amount | No safe dose — any amount | No safe dose — any amount |
| 16 kg (average Border Collie) | No safe dose — any amount | No safe dose — any amount | No safe dose — any amount |
| 20 kg (large Border Collie) | No safe dose — any amount | No safe dose — any amount | No safe dose — any amount |
ℹ️ No established safe dose. Even a single grape has caused acute kidney failure in some dogs. Risk is unpredictable — treat all ingestion as an emergency. Source: ASPCA Animal Poison Control Center dose thresholds. Always confirm with your vet.
Symptoms of Grapes Poisoning in Border Collies
Symptoms typically appear within 6–12 hours of ingestion. Watch for:
Due to Border Collie-specific traits noted above, pay particular attention to neurological signs — seizures, disorientation, or dilated pupils — which the MDR1 mutation can make more severe in Border Collies.
What to Do If Your Border Collie Ate Grapes
- Stay calm and note how much they ate — estimate the amount and type of grapes and your dog's weight. This information is critical for the vet.
- Call ASPCA Poison Control immediately — (888) 426-4435. Available 24/7. A $95 consultation fee may apply, but they will advise whether you need emergency care.
- Do not induce vomiting unless specifically instructed by a vet or Poison Control. Inducing vomiting incorrectly can cause additional harm.
- Go to an emergency vet if symptoms are already present, if a large amount was consumed, or if Poison Control advises it. Find a 24-hour emergency vet near you.
- Bring the packaging of the food or substance if possible — ingredient lists help the vet calculate exact toxin exposure.
Special Considerations for Border Collies
Border Collies with the MDR1 gene mutation require a vet who knows about this — it affects which antidotes and support medications are safe to use. If you don't know your Border Collie's MDR1 status, inform the vet anyway and request that MDR1-sensitive drugs be avoided until testing can be done. This is not a minor detail in a poisoning scenario.
Frequently Asked Questions
There is no safe number. Some dogs have developed acute kidney failure after just one or two grapes, while others appeared unaffected by more. The toxic mechanism is unknown and unpredictable — always call Poison Control.
Yes — raisins are dried grapes and contain a much higher concentration of the toxic compound per gram. Even a small number of raisins can cause kidney failure in a small dog.
The unknown compound in grapes causes acute tubular necrosis — damage to the kidney's filtering cells. This can result in complete kidney failure within 24–72 hours if untreated.
Some dogs appear unaffected while others develop severe kidney failure. Current research cannot predict which outcome will occur — this unpredictability is exactly why all ingestion must be treated as an emergency.