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My 15 kg dog ate a tablespoon of wet coffee grounds — are they worse than if he drank a cup of brewed coffee?

Dogs · Toxicity calculator

Last reviewed: 2026-09-05 · Reference ranges: ASPCA, Pet Poison Helpline & Merck Veterinary Manual

Short answer

Yes, coffee grounds are significantly more dangerous than brewed coffee. Grounds are far more concentrated — a tablespoon can contain many times the caffeine of a cup of liquid coffee, posing a much higher risk of toxicity for a dog his size. Caffeine causes restlessness, a racing heart, tremors, and can lead to seizures. Watch him closely for these signs over the next several hours. If you see any hyperactivity, vomiting, or panting, contact your vet or the ASPCA poison line immediately for guidance, as this can become a serious emergency.

Why is caffeine dangerous for pets?

Caffeine is a methylxanthine (like the theobromine in chocolate) that pets metabolise slowly. It causes hyperactivity, a racing heart and tremors; at high doses it can trigger seizures or cardiac arrhythmia.

Dogs are commonly poisoned by leftover coffee, coffee grounds, or chocolate-covered coffee beans; cats by tea or energy drinks. Grounds and beans are much more concentrated than brewed drinks.

About the dose levels
Reference bands: <1–2 mg/kg usually no signs · ~10 mg/kg can cause restlessness · 30–70 mg/kg more severe · >70 mg/kg risks seizures and arrhythmia. Ground coffee is roughly 3x stronger than brewed by weight.

Signs to watch for

  • Restlessness, hyperactivity, panting
  • Vomiting, increased thirst and urination
  • Racing heart, high temperature, tremors
  • Severe: seizures, collapse, abnormal heart rhythm

What to do right now

  1. Call your vet if the estimated dose is meaningful or any sign appears.
  2. Do not induce vomiting without instruction.
  3. Keep them calm and cool, offer water.
  4. Save packaging (coffee bag, can, bottle) for exact caffeine content.
If your pet shows any of the signs above, go to the nearest emergency vet now and call ahead.

For a dose worked out against your pet's weight, use the Caffeine Toxicity Calculator.

Open the full calculator: Caffeine Toxicity Calculator →