Glossary of terms

A

Activated charcoal. A vet-administered treatment that binds some toxins in the stomach before they're absorbed. Must be given within the first few hours of ingestion. Never attempt this at home — activated charcoal can aspirate into a cat's lungs with fatal results if given incorrectly.

Acute kidney injury (AKI). Sudden loss of kidney function. Lily poisoning is the most common cause in cats — kidneys stop filtering waste, toxins build up, and without treatment within 18–72 hours, damage is irreversible.

Allium. The plant family that includes onions, garlic, leeks, chives, shallots, and spring onions. All alliums cause red blood cell damage (haemolytic anaemia) in cats.

Ataxia. Loss of coordinated movement — wobbliness, staggering, inability to walk straight. A common early sign of many toxicities (alcohol, pseudoephedrine, essential oils).

C

Cholinergic crisis. A set of symptoms — excessive salivation, tears, urination, defecation, miosis (constricted pupils) — caused by certain toxins (organophosphate pesticides, some plants). Needs urgent veterinary care.

Coumarin. A compound in cassia cinnamon and some rat poisons; causes liver injury at high doses and disrupts blood clotting.

D

Dermal exposure. Toxin absorbed through the skin. Essential oils, permethrin, and sunscreen are common dermal exposures in cats — the toxin gets on fur and is then groomed off, compounding dermal with oral exposure.

E

Emesis. Vomiting. 'Induce emesis' in veterinary contexts means giving a specific medication to make the cat vomit — done only by a vet, never at home in cats.

Ethylene glycol. The main toxin in antifreeze. Sweet-tasting, which makes spills attractive. Causes acute kidney failure. Even a teaspoon on paws licked off can be fatal.

G

Glucuronyl transferase. A liver enzyme cats have very low levels of. It's needed to process paracetamol, lilies, and several other toxins — which is why these are far more dangerous to cats than to humans.

H

Haemolysis / Haemolytic anaemia. Destruction of red blood cells. Alliums (onion family), zinc (coins, sunscreen), and paracetamol all cause haemolysis in cats. Pale or yellow gums are the classic sign.

Heinz body. An abnormal structure inside damaged red blood cells, visible on blood smear. A diagnostic marker of allium or paracetamol toxicity.

Hyperthermia. Dangerously high body temperature. Caffeine, chocolate, pseudoephedrine, and some essential oils all cause hyperthermia in cats.

Hypoglycaemia. Dangerously low blood sugar. The signature symptom of xylitol poisoning in dogs; cats are less susceptible but still affected by large doses.

L

LD50. The dose at which 50% of exposed animals die. Used in toxicology to compare relative toxicity. A toxin with an LD50 of 10 mg/kg is much more dangerous than one with LD50 of 1000 mg/kg.

Linear foreign body. A long, thin object (thread, tinsel, ribbon, elastic) swallowed and stuck at one end while peristalsis pulls the rest through — the intestines bunch up and can be cut through by the object. A surgical emergency.

M

Metaldehyde. The main toxin in older slug pellets. Causes rapid onset tremors and seizures. Restricted in outdoor use in the UK since 2022, but old stocks remain in many sheds.

Methaemoglobinaemia. A condition where haemoglobin can't carry oxygen properly. Caused by paracetamol (the number-one cause in cats), alliums, and certain chemicals. Cats develop blue-grey gums and breathing difficulty.

Myristicin. The neurotoxic compound in nutmeg.

N

Nephrotoxin. A substance that damages the kidneys. Lilies, grapes and raisins, ethylene glycol (antifreeze), and NSAIDs are all nephrotoxic to cats.

NSAID. Non-steroidal anti-inflammatory drug. Ibuprofen, naproxen, aspirin. All are toxic to cats, causing kidney injury and stomach ulcers.

O

Obligate carnivore. A species that must eat meat. Cats cannot survive on plant-based diets — they lack the enzymes to make certain vitamins (taurine, vitamin A, arachidonic acid) from plant sources.

P

Pancreatitis. Inflammation of the pancreas. Can be acute (sudden onset) or chronic. Fat-heavy foods (bacon, butter, roast-dinner fat), some medications, and some toxins trigger it. Cats show subtle signs — vomiting, reduced appetite, lethargy — and the diagnosis is often delayed.

Permethrin. The active ingredient in many dog flea spot-on products. Fatal to cats even in tiny amounts. Never use dog flea products on cats.

Photosensitivity. Skin becomes unusually sensitive to sunlight after eating certain substances (parsley in large amounts, some plants). Affected skin develops sunburn-like reactions.

Psoralens. Compounds in citrus and some plants that cause photosensitivity.

R

Rodenticide. Rat or mouse poison. Most modern rodenticides are anticoagulants — they cause bleeding problems over several days. Cats can be poisoned directly by eating bait, or indirectly by eating a poisoned rodent.

S

Solanine. A toxin in green/unripe tomatoes, potato sprouts, and some nightshade plants.

Speakable schema. Not a medical term — a structured-data markup we use so Google Assistant can read answers from our pages aloud in response to voice queries.

T

Theobromine. The main toxin in chocolate. Cats clear theobromine from their system much more slowly than humans do — so amounts that are trivial for us are dangerous for them.

Thiaminase. An enzyme in raw fish that destroys thiamine (vitamin B1). Cats fed regular raw fish can develop thiamine deficiency, which causes neurological signs.

Tremor. Involuntary muscle shaking. A common sign of neurotoxin exposure (metaldehyde, caffeine, pseudoephedrine, chocolate, essential oils).

V

VPIS. Veterinary Poisons Information Service — the UK's vet-only poison reference service. Not accessible to pet owners directly. Cat owners should call the Animal PoisonLine (01202 509000) instead.

X

Xylitol. A sugar alcohol used as a sweetener in chewing gum, some peanut butters, sugar-free sweets, and 'natural' toothpastes. Fatal to cats at small doses. Also called birch sugar, wood sugar, or E967.

If there's a term you've seen used in relation to cat safety that isn't covered here, please let us know and we'll add it.