Reference

Veterinary glossary

Plain-English definitions of the medical and toxicology terms used across this site.

This glossary defines the veterinary and toxicology terms used across this site. Terms are auto-linked to this page on their first appearance in any article.

A

Activated charcoal
A treatment given by vets after poisoning to bind toxins in the stomach and prevent absorption. Only safe when given by a vet — never give it at home.
Ataxia
Loss of coordination or unsteady movement, often a sign of neurological toxicity or severe metabolic disturbance.

C

Cholinergic crisis
Overstimulation of the nervous system caused by organophosphate or carbamate poisoning, presenting as drooling, tremors, constricted pupils, and seizures.
Coumarin
A naturally occurring compound in some plants (and the basis for warfarin-class rodenticides) that interferes with blood clotting.

E

Ethylene glycol
The active toxin in most antifreeze products. Causes fatal kidney failure in cats — even a teaspoon can be lethal.

G

Glucuronyl transferase
A liver enzyme that cats lack in sufficient quantities to process many drugs and chemicals that are safe for humans and dogs. This is why paracetamol and many essential oils are acutely toxic to cats.

H

Haemolysis
Destruction of red blood cells. Caused in cats by onions, garlic, and other allium vegetables — leads to haemolytic anaemia.
Haemolytic anaemia
A form of anaemia caused by destruction of red blood cells. In cats, most commonly caused by allium vegetables (onion, garlic, leeks). Signs include lethargy, pale gums, and rapid breathing.
Heinz body
Abnormal clumps that form inside red blood cells after oxidative damage. A hallmark of allium toxicity in cats, visible on a blood smear.
Hyperthermia
Abnormally high body temperature. Can be caused by stimulants, hops, or extended physical exertion. A medical emergency in cats.
Hypoglycaemia
Dangerously low blood sugar. Can be caused by xylitol ingestion (via insulin release) or severe illness. Signs include weakness, tremors, and seizures.

L

Linear foreign body
String, ribbon, tinsel, or thread that becomes lodged in the digestive tract. Highly dangerous — can cause the intestine to bunch or perforate. Never pull on visible string from a cat's mouth or anus.

M

Metaldehyde
The active toxin in slug pellets. Causes muscle tremors, hyperthermia, and seizures in cats.
Methaemoglobinaemia
A condition in which haemoglobin is oxidised to a form that cannot carry oxygen, causing the blood to turn brown. Caused in cats by paracetamol — a medical emergency.
Myristicin
A compound in nutmeg (and parsley, to a lesser extent) that is hallucinogenic and toxic to cats at even small doses.

N

Nephrotoxin
A substance that damages the kidneys. Lilies are the most dangerous nephrotoxins for cats.
Nsaid
Non-steroidal anti-inflammatory drug (e.g. ibuprofen, aspirin, naproxen). Cats are extremely sensitive to NSAIDs — even a small dose can cause stomach ulceration, kidney failure, or death.

O

Obligate carnivore
An animal that must eat meat to survive — their bodies cannot synthesise all the nutrients they need from plant sources. Cats are obligate carnivores and cannot thrive on a vegan diet.

P

Pancreatitis
Inflammation of the pancreas, often triggered by high-fat foods. Causes severe abdominal pain, vomiting, and lethargy.
Permethrin
An insecticide used in many dog flea treatments that is acutely toxic to cats. Never apply a dog flea product to a cat.
Photosensitivity
Increased sensitivity to UV light, causing skin inflammation in lightly-pigmented or white-eared cats exposed to certain plants or substances.
Psoralens
Photoactive compounds found in citrus peel and some other plants that cause phototoxic skin reactions.

R

Rodenticide
Rat or mouse poison. The most common types (anticoagulant rodenticides) cause internal bleeding. Others (bromethalin) cause neurological damage. All are potentially lethal to cats.

S

Solanine
A glycoalkaloid toxin found in the green parts of tomatoes and potatoes, and in the nightshade family generally. Causes gastrointestinal distress and nervous system effects.

T

Theobromine
The primary toxin in chocolate, also present in tea. Cats metabolise it far more slowly than humans. Causes heart arrhythmias, tremors, and seizures.
Thiaminase
An enzyme found in raw fish that destroys thiamine (vitamin B1). Regular feeding of raw fish can cause thiamine deficiency, leading to neurological signs.

V

Vpis
Veterinary Poisons Information Service — a 24-hour telephone service for vets dealing with animal poisoning cases. Your vet calls VPIS directly; it is not available to members of the public.

X

Xylitol
An artificial sweetener used in sugar-free products, chewing gum, and some peanut butters. Causes a dangerous insulin surge and hypoglycaemia in many animals, though cats appear less sensitive than dogs — still avoid.