Federal authorities are warning pet owners to avoid a product that has killed five dogs that ate some of it. It is a cream called fluorouracil that is used to treat and prevent skin cancer, and is often sold under the brand names Carac, Efudex and Fluroplex, the Food and Drug Administration said in a statement.

The FDA noted that in one case, two dogs were playing with a tube of fluorouracil when one punctured the tube. Within two hours, the dog started to vomit and experienced seizures, dying in just 12 hours. In another case, the dog found the tube and ate it. The owner rushed the dog to a veterinarian, but the dog got too sick and had to be euthanized.

The FDA warns even small amounts can be dangerous to pets. The drug works by killing fast-growing cells, which includes skin cancer and other dangerous growths. The FDA is also warning cat owners to be careful, although there have been no reported deaths from fluorouracil.

“The U.S. Food and Drug Administration is alerting pet owners, veterinarians, health care providers and pharmacists that pets are at risk of illness and death when exposed to the topical cancer medication Fluorouracil Cream USP 5% (5-FU.) intended for use in people,” the FDA statement notes. “Fluorouracil may also be marketed under the brand names Carac, Effudex and Fluoroplex. People using this medication should use care when applying and storing the medication if they are also in a household with pets, as even very small amounts could be dangerous to these animals.

“The FDA has received reports of five dogs that became ill and died after accidentally ingesting the topical cream,” it continues. “In one case, two dogs began playing with a tube of Fluorouracil and one punctured the tube before their owner could retrieve it. Within 2 hours, the dog that punctured the tube began vomiting, experienced seizures, and died 12 hours later. In a separate case, a dog located his owner’s tube of Fluorouracil and ingested its contents. The owner realized the dog had ingested the medication and rushed him to the veterinarian. The veterinarian attempted treatment, but the dog’s condition declined over three days and he was ultimately euthanized.”