Ibuprofen poisoning in dogs and cats
Toxic agent: Ibuprofen, a non-selective NSAID · Reviewed 2026-08-18
Phone a vet now, before reading on. Have ready: your pet's weight, roughly how much was eaten and when, and the packaging if there is any. ASPCA Animal Poison Control (+1 888 426 4435), Pet Poison Helpline, or Animal PoisonLine in the UK.
Ibuprofen strips the stomach of its own protection and then attacks the kidneys. Dogs are far more sensitive than people, and the margin between a human dose and a bleeding ulcer is narrow.
What it actually does
Ibuprofen blocks both COX-1 and COX-2. COX-2 inhibition is the pain relief; COX-1 inhibition removes the prostaglandins that maintain the stomach's mucus layer and the blood flow through the kidneys. So the same molecule causes the ulcer and the renal injury, and in dogs the drug persists long enough for both.
How much matters
Three thresholds, each opening a new problem:
| From about 50–100 mg/kg | gastrointestinal ulceration |
|---|---|
| From about 175 mg/kg | acute kidney injury |
| From about 400 mg/kg | seizures and central nervous system signs |
| One 200 mg tablet in a 5 kg dog | 40 mg/kg — already at the edge of the first threshold |
Cats are roughly twice as sensitive as dogs. There is no situation in which a household ibuprofen tablet is the right analgesic for either species.
What you will see, and when
Onset: 2 to 6 hours for gastrointestinal signs; kidney values move over 12–48 hours. Typical course: Treatment commonly 48–72 hours, longer if an ulcer has perforated.
- 2–6 hoursVomiting, sometimes with blood or coffee-ground material, abdominal pain, loss of appetite
- 12–24 hoursBlack tarry stools, pale gums, weakness
- 24–48 hoursIncreased thirst and urination, then falling urine output as the kidneys fail
What the vet will do
Decontamination if recent, then a proton pump inhibitor and a protectant such as sucralfate to give the stomach lining a chance, intravenous fluids to defend the kidneys, and repeated blood work. Intravenous lipid emulsion is sometimes used for large ingestions. There is no antidote.
Outlook
Good for gastrointestinal-only cases treated early. Guarded once the kidneys are involved, poor with a perforated ulcer.
Dogs and cats are not the same here
Cats about twice as sensitive as dogs, and cats hide gastrointestinal pain well, so presentation is often later and worse.
Where it comes from in a normal house
- Advil, Nurofen, Motrin and supermarket own-brand tablets
- Liquid ibuprofen for children, which is easy to lick up
- Combination cold remedies
- Handbags and gym bags — the most common route is a dropped tablet
The thing people get wrong
“It is a mild painkiller, so a small dose will help a limping dog.”
It is mild in a species with different prostaglandin biology. Veterinary NSAIDs exist, are dosed for dogs and are far safer; giving ibuprofen for a limp regularly turns one problem into three.
PawLife keeps your pet's weight, medication and feeding history in one place, so when you make this call you can answer the vet's questions in seconds. The full food safety database is free.
Get PawLife on the App StoreFrequently asked questions
How much Ibuprofen is dangerous?
Cats are roughly twice as sensitive as dogs. There is no situation in which a household ibuprofen tablet is the right analgesic for either species.
How long after exposure to Ibuprofen do symptoms start?
2 to 6 hours for gastrointestinal signs; kidney values move over 12–48 hours. Vomiting, sometimes with blood or coffee-ground material, abdominal pain, loss of appetite. Treatment commonly 48–72 hours, longer if an ulcer has perforated.
Is Ibuprofen worse for cats or dogs?
Cats about twice as sensitive as dogs, and cats hide gastrointestinal pain well, so presentation is often later and worse.
Is it true that: It is a mild painkiller, so a small dose will help a limping dog.
It is mild in a species with different prostaglandin biology. Veterinary NSAIDs exist, are dosed for dogs and are far safer; giving ibuprofen for a limp regularly turns one problem into three.
Related emergencies
Sources
This page is information, not veterinary advice. Toxic doses vary with body weight, age, breed and individual sensitivity, and the figures above exist to explain what a vet is assessing, never to decide that an amount is safe. If you are reading this because something has already been eaten, call a vet.