Home › Can my pet eat this? › 5-Fluorouracil Cream (5-FU)
🧴 Is 5-FU skin cream poisonous to dogs and cats?
🔴 Yes. It's dangerous.
👉 What to do right now
- CRITICAL LEVEL 1 EMERGENCY.
- No antidote.
- Even partial tube contact can be fatal.
- Go to emergency vet immediately — do not wait for symptoms.
⛔ Don't
- Wait even one minute
- Induce vomiting if seizures are present
⚖️ How much is too much?
Harmful amounts depend on your pet's body weight.
🐶 DogsMinimum toxic: 8.6mg/kg; lethal: 20mg/kg
🐱 CatsAny contact — most cats die from very small exposures
👀 Signs to watch for
- Hemorrhagic vomiting and diarrhea (30–60 min)
- Tremors
- Intractable seizures
- Bone marrow suppression (delayed 4–7 days)
⏱️ When do signs show up?
30–60 minutes
🔬 Why is it harmful?
Analog of uracil/thymidine that inhibits DNA/RNA synthesis. Metabolized to fluorocitrate which blocks the Krebs cycle and depletes GABA, causing intractable seizures. Minimum lethal dose in dogs: 20mg/kg.
🕵️ Where it hides
- Efudex cream
- Carac cream
- Fluoroplex cream
- Any topical used for actinic keratosis or skin cancer treatment
Related
Informational triage only. Does not replace professional veterinary diagnosis. When in doubt, always call your vet.