Suspect poisoning? US: ASPCA Poison Control (888) 426-4435 · UK: 01202 509 000 · Severe symptoms → nearest emergency vet now.

My cat licked a small puddle of sugar-free energy drink that was left out overnight — is stale caffeine still toxic?

Cats · Food safety

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

Short answer

Yes, it is absolutely still toxic. Caffeine and other stimulants in energy drinks do not lose their potency by being left out; they remain highly dangerous to cats. Even a small amount can cause rapid heart rate, tremors, or seizures. The 'sugar-free' aspect doesn't make it safer—the artificial sweeteners and other compounds are also a concern. This is an emergency. Contact your veterinarian or the ASPCA Animal Poison Control Center at 888-426-4435 immediately, and be ready to describe what she licked and how much.

Energy drinks — Food safety facts

Do not feed · Cats · full breakdown on the linked food page

Caffeine, taurine and sugar together — a cardiac emergency in small pets.

Dogs and cats carry the same rating (Do not feed), so the notes below hold for either pet.

Energy drinks should not be given to cats at all. Even a small amount can do harm, so there is no portion small enough to be safe.

Do not induce vomiting and do not give milk or oil to “dilute” it. Note the food and roughly how much was eaten, then call your vet or a pet poison hotline and follow their advice on whether to bring the pet in straight away.

Why these cautions matter

Caffeine overstimulates the heart and nervous system, and pets clear it so slowly that tremors and restlessness drag on far longer than they would in a person.

Added sugar brings empty calories, and over months that means weight gain and dental disease — both far harder to undo than to avoid.

Energy drinks has no place in everyday feeding: keep the rest of the day's food unchanged after this and watch the litter box and how quickly they finish the next meal.

The full verdict, portion guidance and serving notes are collected on the Energy drinks food facts page.

Open the full food page: Energy drinks food facts →