Can dogs eat grapes?

How much is dangerous?

There is no established safe dose. Merck states that more than one grape or raisin per 4.5 kg (10 lb) of body weight may contain enough tartaric acid to risk kidney injury, but individual dogs have developed renal failure after far less, and others have eaten large amounts with no effect. Treat any ingestion as needing veterinary advice.

Why it does harm

Tartaric acid and potassium bitartrate are the proposed toxic principle. Wegenast et al. reported acute kidney injury in dogs after ingesting cream of tartar and tamarinds, which share that compound with grapes. Merck notes that tartaric acid content varies between fruit, which is why the effects are so inconsistent.

What to look for

• Vomiting or diarrhea, often within 6 to 12 hours
• Lethargy and loss of appetite
• Abdominal pain and weakness
• Increased thirst
• Reduced or absent urination as kidney injury develops

Timing. Vomiting or diarrhea in 6 to 12 hours; kidney failure can follow within 24 to 48 hours.

What to do

1. Call a vet or a poison control line now. Do not wait to see whether your dog seems unwell.
2. Take the packaging, or note the type and rough amount of fruit.
3. Early decontamination and intravenous fluids are what change the outcome, and both are time-critical.

Sources

• Merck Veterinary Manual. Grape, Raisin, and Tamarind (Vitis spp, Tamarindus spp) Toxicosis in Dogs.
• Wegenast CS, Meadows ID, Anderson RE, Southard T, González Barrientos CR, Wismer TA. Acute kidney injury in dogs following ingestion of cream of tartar and tamarinds and the connection to tartaric acid as the proposed toxic principle in grapes and raisins. J Vet Emerg Crit Care. 2022;32(6):812–816.
• ASPCA Animal Poison Control Center. People foods to avoid feeding your pets.