What you need to know

Not all seizures are caused by epilepsy. A category of seizures called reactive seizures occurs when an otherwise neurologically normal brain is exposed to a toxic substance or metabolic disruption. Many of the triggers for reactive seizures in pets are found in ordinary homes — in kitchens, gardens, medicine cabinets, and garages.

Understanding which substances are seizure risks — and acting quickly when exposure occurs — can be life-saving. This guide covers the most commonly documented toxic triggers for seizures in dogs and cats based on veterinary toxicology literature and emergency medicine guidelines. Note that toxicity evidence differs by species: some of these risks are best documented in dogs, and cats may have different sensitivities. When in doubt about any substance and your individual pet, contact a poison control hotline or your veterinarian.

Foods that can cause seizures in dogs

Xylitol (artificial sweetener)

Xylitol is one of the most dangerous substances for dogs. Found in sugar-free gum, candies, certain peanut butters, baked goods, mouthwash, and some medications, xylitol causes a rapid and severe drop in blood sugar (hypoglycemia) in dogs — which can trigger seizures. It also causes acute liver failure. Dogs are significantly more sensitive to xylitol than humans. Even small amounts can be dangerous. Always check ingredient labels before giving any human food product to a dog.

Chocolate and caffeine

Chocolate contains theobromine and caffeine, both of which are toxic to dogs in sufficient amounts. Dark chocolate and baking chocolate contain the highest concentrations. Signs of toxicity include agitation, muscle tremors, and seizures. The amount required to cause seizures varies by the dog's body weight and the type of chocolate — but there is no safe amount to offer as a treat.

Grapes and raisins

While the mechanism is not fully understood, grapes and raisins can cause acute kidney failure in dogs, which secondarily can cause neurological signs including seizures. Sensitivity varies between individual dogs — some appear unaffected, while others develop serious illness after small amounts. The current veterinary recommendation is to treat any grape or raisin ingestion as potentially serious.

Macadamia nuts

Macadamia nuts cause a syndrome in dogs that includes weakness, hyperthermia, vomiting, and tremors. While seizures are less common than with other toxins, neurological involvement has been reported. The toxic dose is not well established.

Alcohol

Alcohol — including ethanol in beverages, hand sanitizers, and fermented foods — is toxic to dogs and cats and can cause CNS depression, low blood sugar, and seizures.

Household substances that can trigger seizures

Permethrin (insecticides)

Permethrin is commonly found in flea and tick products labeled for dogs. It is highly toxic to cats — even small amounts of permethrin-containing dog products applied to or near cats can cause severe neurological signs including tremors and seizures. Never use dog flea products on cats or in environments where cats may be exposed.

Slug and snail bait (metaldehyde)

Metaldehyde, found in many garden slug and snail pellets, is highly toxic to dogs and causes severe, rapid-onset tremors and seizures. It is considered one of the most dangerous garden toxins for pets. Keep all garden pesticides locked away and consider pet-safe alternatives.

Rodenticides (rat and mouse poison)

Several types of rodenticides cause neurological signs in pets. Bromethalin-based rodenticides specifically cause brain swelling and can result in tremors and seizures. Anticoagulant rodenticides (warfarin-based) can cause bleeding into the brain. If you use rodenticides, keep them completely inaccessible to pets.

Human medications

Many human medications are toxic to pets and can cause seizures, including:

• NSAIDs — Ibuprofen, naproxen (Advil, Aleve) — never give to pets
• Antidepressants — Various classes can cause serotonin syndrome and seizures
• ADHD medications — Amphetamine-based drugs are highly toxic to pets
• Sleep aids and muscle relaxants
• Topical creams — Some hormone creams, 5-fluorouracil (cancer cream) — extremely toxic to pets

Keep all human medications in closed cabinets, never leave pills on counters, and never give human medications to pets without explicit veterinary guidance.

Toxic plants

Several common garden and houseplants can cause neurological signs in pets. Of particular concern for seizure risk are sago palm (extremely toxic to both dogs and cats; causes liver failure), cycad palms, and blue-green algae (from contaminated water sources). The ASPCA maintains a comprehensive toxic plant database at aspca.org/pet-care/animal-poison-control/toxic-and-non-toxic-plants.

Seizures caused by metabolic disruption

Reactive seizures in pets can also be triggered by internal metabolic conditions rather than ingested toxins:

• Hypoglycemia — Low blood sugar, particularly in puppies, small breeds, and diabetic pets
• Liver disease — Hepatic encephalopathy from toxin accumulation
• Kidney disease — Uremic encephalopathy in severe kidney failure
• Electrolyte imbalances — Particularly sodium abnormalities
• Hypocalcemia — Low calcium, particularly in lactating females (eclampsia)