When to see a vet urgently
Suspected exposure to a kidney toxin requires immediate contact with a vet, even if your cat still seems healthy. Particularly worrying signs include:
- repeated vomiting or suddenly refusing food;
- unsteadiness, trembling, seizures or unusual sleepiness;
- a marked decrease in urine output or no urine at all;
- a collapse in general condition or difficulty breathing.
Do not wait for every sign to appear. Take details of the exposure with you and find a vet near you.
Overview
The kidneys act as a filter, removing toxins and metabolic waste from the body. Kidney toxins destroy the renal tubules and glomeruli, sharply reducing filtration. Metabolic waste builds up in the blood (azotaemia), toxic effects develop, and fluid and salt balance is disrupted. Depending on the amount and substance involved, the damage may be reversible or progress to chronic kidney failure.
Sudden kidney damage is called acute kidney injury, or AKI. It can begin before blood tests show a clear rise in waste products. The renal tubules process filtered fluid and regulate the reabsorption of water and salts. Damage to them can therefore change the amount and composition of urine even while your cat is still urinating.
Toxicity depends on the substance. Cats' different metabolism does not mean that they eliminate every chemical equally slowly. A substance on the coat can also enter the mouth when a cat grooms. Some poisons damage other organs as well as the kidneys.
Causes
The most common substances toxic to cats' kidneys include:
- Ethylene glycol (in antifreeze) – one of the most common causes of fatal poisoning.
- Plants – true lilies (Lilium) and daylilies (Hemerocallis): every part of the plant, its pollen and even vase water are toxic to cats.
- Medicines:
- non-steroidal anti-inflammatory drugs, or NSAIDs (ibuprofen, acetylsalicylic acid, naproxen),
- antibiotics (aminoglycosides),
- chemotherapy drugs,
- some antiparasitic medicines.
- Heavy metals and household chemicals.
Simply placing lilies on a high shelf does not remove the risk: pollen can fall onto surfaces and your cat's coat. Not every plant with “lily” in its name causes the same kidney damage. Accurate identification is still important, as other species can have different dangerous effects. Take a photograph of the plant or its label to the appointment.
Compounds produced when ethylene glycol is metabolised damage the renal tubules and disrupt the body's acid balance. Calcium oxalate crystals can form in the urine. Early unsteadiness can resemble drunkenness, but a temporary improvement does not mean that the poison has been safely eliminated.
NSAIDs can damage the stomach and intestines as well as the kidneys. Vomiting or loss of appetite after receiving a medicine therefore does not, on its own, show which organ is affected. Report the change to the treating vet and confirm whether and how to continue the medication.
NSAIDs can reduce the action of substances that maintain blood flow to the kidneys. The risk is greater in a patient with dehydration or impaired circulation, for example. A prescribed veterinary medicine and an accidentally swallowed human medicine are assessed differently: always give the exact product name and details of other medicines your cat is taking.
Risk factors
- Cats with free access outdoors or to a garage (risk of antifreeze exposure).
- Homes containing poisonous plants.
- Owners treating their cats themselves with human medicines.
- Older cats and cats with chronic kidney disease.
Existing kidney disease and concurrent dehydration can also increase the risk of harm from certain medicines. This does not mean that every antibiotic or antiparasitic medicine damages the kidneys. The active ingredient, amount given, route of administration and your cat's other health circumstances all matter. Old age is not a prerequisite for poisoning: a young, healthy cat can also suffer severe damage.
Even an indoor cat may reach a dropped tablet, an open medicine packet or a bouquet. Assessing the risk means considering the whole home and visitors' belongings, as well as outdoor access.
Typical symptoms
- lethargy and apathy;
- refusing food and vomiting;
- excessive urination or, conversely, little or no urine (oliguria/anuria);
- thirst and dehydration;
- abdominal pain and muscle tension;
- trembling and seizures in severe poisoning;
- an ammonia smell on the breath;
- coma and death in severe cases.
Symptoms do not reliably identify the poison or the extent of damage. Early vomiting caused by lilies may settle before declining kidney function becomes apparent. Continued urination or drinking therefore does not rule out poisoning. Conversely, excessive urination can increase dehydration, even if you associate kidney failure only with an inability to pass urine.
Complications and consequences
- acute kidney failure;
- chronic kidney failure if the cat survives the poisoning;
- liver and nervous system damage;
- death if treatment is delayed.
Low urine production can lead to a dangerous build-up of potassium in the blood. Changes in acidity and other salts also need monitoring. Survival does not automatically mean permanent kidney disease, but some cats are left with reduced function. The prognosis depends on the extent of damage, urine production and changes during treatment.
Diagnosis at the vet
- history, including known or suspected contact with a poison;
- a full blood count and blood biochemistry (azotaemia and electrolyte disturbances);
- urinalysis (changes in specific gravity, protein, casts and blood);
- kidney ultrasound (swelling and structural changes);
- toxicological testing of stomach contents or urine.
Combining exposure details and test results
Tell the vet what your cat may have swallowed or licked, when the exposure happened and how much may have been involved. Bring the packaging or a photograph of the ingredient list. Also mention medicines already given and anything you have done at home. An incorrect guess about the product can be misleading, so state clearly when you are unsure.
A rapid test is not available for every poison, and toxicological testing is not an essential first investigation for every patient. The time since exposure affects the chance of detecting ethylene glycol. A well-founded suspicion of poisoning may require treatment before final confirmation.
A urine sample can be examined for cells and casts that suggest tubular damage. Casts are moulds formed within the tubules. For example, glucose may enter the urine when tubular reabsorption is impaired. Findings are interpreted alongside blood glucose and other investigations; a single abnormality cannot reliably identify a particular poison.
Blood and urine tests may need repeating because an early result alone does not reflect damage that develops later. Ultrasound helps assess structure and urine flow, but does not usually identify the swallowed substance. Other causes of acute kidney injury, such as urinary obstruction or infection, are investigated at the same time.
Treatment and monitoring recovery
Treatment begins with an assessment of the exposure and your cat's condition. Prevent further access to the substance and contact a vet immediately. Do not try to induce vomiting or give medicines or home remedies yourself. Measures to reduce absorption depend on the substance, timing and level of consciousness; activated charcoal, for example, does not bind ethylene glycol effectively.
Treatment targeting a particular poison is chosen separately. There is no specific antidote to lily poisoning, whereas ethylene glycol metabolism can be interrupted at an early stage. An antidote alone cannot repair advanced kidney damage, however.
In hospital, acid–base balance can also be monitored and disturbances corrected. The support needed may change during treatment, so the same cat needs repeated assessments.
Fluid therapy is adjusted according to dehydration, weight, blood results and measured urine production. A cat producing no urine cannot safely receive unlimited fluid to “flush the kidneys”. Excess fluid can accumulate in the body and make the situation worse. In severe cases, the need for and availability of dialysis, a treatment that cleans the blood, may be assessed.
Nausea and pain are treated, and nutrition is supported with assisted feeding if necessary. Urine production can be high during recovery, requiring continued monitoring of fluid balance. At discharge, follow-up tests and instructions for changes in appetite, urination and general condition are agreed. Leaving hospital does not yet prove that kidney function has fully recovered.
Prevention
- Never give your cat human medicines without a vet's prescription.
- Prevent access to antifreeze, household chemicals and fertilisers.
- Remove plants dangerous to cats, particularly lilies, from your home.
- Keep all medicines and chemicals out of your cat's reach.
- Arrange regular checks for cats at risk, including older cats and those with chronic kidney disease.
Also keep visitors' bags, pill organisers and chemicals used during repair work out of your cat's reach. Clean up spills and prevent access to the area while cleaning. Suspected exposure needs immediate assessment; a routine check-up for an at-risk cat cannot replace urgent treatment for poisoning.
Important for cat owners
Nephrotoxicity is a common cause of acute kidney failure and death in cats. Remember: even a small amount of antifreeze, a single lily flower or an ibuprofen tablet can be fatal. If you suspect poisoning, take your cat straight to a clinic or emergency vet – hours matter. Preventing access to poisons is the best protection.
This article provides general information and does not replace veterinary care. Contact a vet immediately if you suspect poisoning.
Frequently asked questions
Can lily pollen damage a cat's kidneys?
Yes. Pollen from dangerous lilies can enter the mouth during grooming. Vase water is also a risk. Contact a vet immediately, even if you have not seen your cat eat the plant.
Can I wait if my cat seems brighter after vomiting?
Do not wait after suspected exposure. Temporary relief of symptoms does not show that the kidneys are safe. Treatment options depend on the substance and the time elapsed, so report the suspected exposure immediately.
Can the kidneys recover after poisoning?
Recovery is possible, but cannot be promised in advance. Some cats are left with chronic kidney disease. Your vet assesses recovery from urine production, test results and changes in your cat's condition.
This article is for general information only and is not a guide to treatment. If you notice the first signs of illness, contact your vet.
Paw4care editorial team
Sources
- Lovely Lilies and Curious Cats: A Dangerous Combination, U.S. Food and Drug Administration, accessed 2026-11-05.
- Ethylene Glycol Toxicosis in Animals, Merck Veterinary Manual, accessed 2026-11-05.
- Feline acute kidney injury: 1. Pathophysiology, etiology and etiology-specific management considerations, Journal of Feline Medicine and Surgery / PubMed Central, accessed 2026-11-05.
- Renal Dysfunction in Dogs and Cats, Merck Veterinary Manual, accessed 2026-11-05.
- Cat poisoning: symptoms and how to spot it, Cats Protection, accessed 2026-11-05.
- Poisons, Cornell University College of Veterinary Medicine, accessed 2026-11-05.
- Get the Facts about Pain Relievers for Pets, U.S. Food and Drug Administration, accessed 2026-11-05.
- Acute Kidney Injury in Cats, VCA Animal Hospitals, accessed 2026-11-05.