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.
Shih Tzus are brachycephalic — their flat facial structure restricts airflow and makes respiratory compromise from vomiting or toxic exposure more dangerous than in longer-nosed breeds. They are curious and bold for their size, often accessing food left unattended. Their kidney function can also be more sensitive than many breeds, making renal-toxic substances especially dangerous.
Why Does Breed Matter for Grapes Toxicity?
Toxic doses for grapes are calculated per kilogram of body weight. A Shih Tzu typically weighs 4–7.5 kg, which directly determines how much an unknown nephrotoxic compound their body is exposed to relative to their size. Beyond weight, Shih Tzus 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 Shih Tzu breed, a significant weight difference changes the risk calculation meaningfully.
How Much Grapes Is Toxic to a Shih Tzu?
These thresholds are based on the typical Shih Tzu weight range of 4–7.5 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 |
|---|---|---|---|
| 4 kg (small Shih Tzu) | No safe dose — any amount | No safe dose — any amount | No safe dose — any amount |
| 5.5 kg (average Shih Tzu) | No safe dose — any amount | No safe dose — any amount | No safe dose — any amount |
| 7.5 kg (large Shih Tzu) | 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 Shih Tzus
Symptoms typically appear within 6–12 hours of ingestion. Watch for:
Due to Shih Tzu-specific traits noted above, pay particular attention to any signs of breathing difficulty — their flat faces mean respiratory compromise can escalate rapidly compared to other breeds.
What to Do If Your Shih Tzu 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 Shih Tzus
Like all brachycephalic breeds, Shih Tzus have increased aspiration risk during vomiting. Vets may use different decontamination protocols than they would for non-brachycephalic dogs. Their documented kidney sensitivity also means that renal-toxic substances (like grapes or certain NSAIDs) warrant aggressive fluid support and close monitoring of kidney values.
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.