What are the symptoms of 5-fluorouracil cream poisoning in cats?

vomiting, tremors, seizures, collapse

5-fluorouracil cream

Q: What if my cat ate 5-fluorouracil cream?

Dangerous: Never — tiny amounts of 5-FU cream are often fatal to cats. Fluorouracil (Efudex, Carac) is a chemotherapy cream for human skin lesions. Cats lick it off a person’s skin or chew the tube. Reported cases progress from vomiting to severe neurologic signs and death, sometimes after a single exposure. This is one of the highest-risk medicines in a bathroom drawer. Source: ASPCA.

Q: Is Topical NSAID creams also safe for cats?

Dangerous: Dangerous — cats lick diclofenac and similar gels off skin and furniture.

Dangerous

Verdict

Never — tiny amounts of 5-FU cream are often fatal to cats.

Toxic principle: 5-fluorouracil (5-FU)

Also called: 5-fu, efudex, carac, fluorouracil

Source: ASPCA · Verified 2026-08-13

If your cat ate this

Cats hide symptoms — don't wait and see. Even small amounts of certain substances can be fatal to a cat. Act fast.

1. Call your veterinarian immediately
US — National hotline: ASPCA Animal Poison Control Center (888) 426-4435 aspca.org(24/7, Consultation fee may apply.)
US — National hotline: Pet Poison Helpline (855) 764-7661 petpoisonhelpline.com(24/7, $89 per incident fee; also covers Canada.)
GB — National hotline: Animal PoisonLine 01202 509 000 animalpoisonline.co.uk(24/7, £35 per call (8am–8pm weekdays), £45 at other times.)
AU — National hotline: Animal Poisons Helpline 1300 869 738 animalpoisons.com.au(24/7)
NZ — National hotline: Animal Poisons Helpline 0800 869 738 poisons.co.nz(11am–7pm NZ time (currently being extended), Charges apply.)
CA — National hotline: Pet Poison Helpline (855) 764-7661 petpoisonhelpline.com(24/7, $89 per incident fee.)

Verified 2026-08-06

Verdict

Fluorouracil (Efudex, Carac) is a chemotherapy cream for human skin lesions. Cats lick it off a person’s skin or chew the tube. Reported cases progress from vomiting to severe neurologic signs and death, sometimes after a single exposure. This is one of the highest-risk medicines in a bathroom drawer.

Symptoms to watch for

• vomiting
• tremors
• seizures
• collapse

What to do

Emergency even if the amount looked tiny. Call a vet or poison control immediately.

ASPCA Animal Poison Control Center: (888) 426-4435 aspca.org

Related foods

Topical NSAID creams

Dangerous

Dangerous — cats lick diclofenac and similar gels off skin and furniture.

Topical

Acetaminophen (Tylenol)

Dangerous

Never — a single regular-strength tablet can kill a cat.

Pain relievers

Ibuprofen

Dangerous

Never — NSAIDs ulcerate the gut and injure feline kidneys.

Pain relievers

Naproxen (Aleve)

Dangerous

Never — a long-acting NSAID with the same gut and kidney risks as ibuprofen.

Pain relievers