Also sold as Efudex, Carac, Fluoroplex, Tolak, 5-FU
At amounts a dog can reach in a normal household, this needs a vet or poison-control call straight away rather than watching and waiting.
This is one of the most dangerous things in an ordinary bathroom. A chewed tube of 5-fluorouracil cream can kill a dog, and the effects begin within an hour. Treat any exposure, including a licked hand, as an immediate emergency.
Call a vet or poison control now. Do not wait for symptoms.
ASPCA Animal Poison Control (888) 426-4435 or Pet Poison Helpline (855) 764-7661. A consultation fee may apply.
Source-backed guidance. Not individualized veterinary advice.(more)
Compiled from veterinary poison-control and medical references, including the ASPCA Animal Poison Control Center, Pet Poison Helpline, and Merck Veterinary Manual.
Part of Steroids, immunosuppressants and skin treatments on our medication safety hub.
Do not wait for symptoms and do not wait until you have filled in the form below. Call first, then use the checklist while you are on the phone.
Available 24/7. A consultation fee may apply.
Exposure details to have ready
These are the questions a veterinarian or poison-control operator will ask. Fill in what you know and leave the rest blank. This tool does not estimate a dose or a risk score: medication risk depends on the exact ingredient, strength, and formulation, so the assessment has to come from the clinician on the call.
- Keep the package, blister pack, or prescription bottle. The strength and the full ingredient list are what make the advice specific.
- Do not induce vomiting unless a veterinarian or poison-control professional tells you to. It is the wrong move for several medications and can cause harm on its own.
- Do not give milk, food, salt, hydrogen peroxide, or any home remedy on your own.
- Do not give a second dose of anything to make up for one you think was missed.
- Count what is left in the packet, so the number missing can be worked out.
Your exposure summary
Read this down the phone or paste it into a message to your vet. It stays on your device; nothing here is sent to DogSafe.
Why Fluorouracil Cream (5-FU) is dangerous
Fluorouracil is a chemotherapy agent, and the skin cream prescribed for sun-damaged skin and precancerous lesions contains a great deal of it. Dogs are extremely sensitive: exposure causes severe vomiting, often bloody, followed rapidly by tremors and seizures that are difficult to control, and then bone-marrow failure in animals that survive the first phase. Onset is measured in minutes to hours rather than days, and the prognosis is poor once seizures begin. Discarded applicators and tissues are as much of a hazard as the tube.
Signs to watch for
Signs may be delayed. Depending on the drug: bruising, pale gums, blood in urine or stool, weakness, collapse, tremors, seizures, or changes in breathing or heart rhythm
Related items
Check the exact item or ingredient before assuming two similar exposures carry the same risk.
What to do next
Call first. Then find the packet, count what is left, note the strength and the time, and keep the container to hand for the call.
🚨Step-by-step: what to do in the first 10 minutes →Available 24/7. A consultation fee may apply.
A closer look at fluorouracil cream (5-fu)
Fluorouracil is a chemotherapy agent, and the skin cream prescribed for sun-damaged skin and precancerous lesions contains a great deal of it. Dogs are extremely sensitive: exposure causes severe vomiting, often bloody, followed rapidly by tremors and seizures that are difficult to control, and then bone-marrow failure in animals that survive the first phase. Onset is measured in minutes to hours rather than days, and the prognosis is poor once seizures begin. Discarded applicators and tissues are as much of a hazard as the tube. The details below use the specific facts for this exposure, rather than treating it like every other medication question.
1. Start with the exact exposure
For a closely related comparison, read Methotrexate. Do not look for a threshold here. This is a drug where a plausible household exposure is treated as urgent regardless of the number of tablets, and where the delay before signs appear is part of the hazard rather than a reassurance.
2. Use the facts to decide whether to monitor or call
Another helpful reference is Colchicine. There is nothing to manage at home. Call a vet or an animal poison-control line now, before symptoms, and do not induce vomiting unless they instruct you to. Immediately, whether or not your dog seems unwell. A normal-looking dog in the first hours is not evidence that the exposure was small.
3. If the details are uncertain
Follow the first 10 minutes guide. Call first. Then find the packet, count what is left, note the strength and the time, and keep the container to hand for the call.
FAQ
Do not look for a threshold here. This is a drug where a plausible household exposure is treated as urgent regardless of the number of tablets, and where the delay before signs appear is part of the hazard rather than a reassurance.
There is nothing to manage at home. Call a vet or an animal poison-control line now, before symptoms, and do not induce vomiting unless they instruct you to.
Immediately, whether or not your dog seems unwell. A normal-looking dog in the first hours is not evidence that the exposure was small.
Treat it as an emergency and call now. This is a drug where very small exposures have caused serious illness in dogs, and the interval in which treatment helps is short. Do not wait to see whether signs appear.
- Merck Veterinary Manual — poisonings from human prescription and over-the-counter drugs
- ASPCA Animal Poison Control Center — human medications
- FDA Center for Veterinary Medicine — extra-label drug use in animals
- Merck Veterinary Manual: Poisonings from human prescription drugs
- ASPCA Animal Poison Control
- FDA: The ins and outs of extra-label drug use in animals