I recently received a query about a cat suffering from scabs at the base of her tail and around her face and neck. The reader was concerned about the scabs, which seemed to be itchy. The reader wondered — can you put Neosporin on cats?

The answer to his question is no, and I’ll get to that in a moment. I wrote back to the reader and told him that the distribution of scabs (along with the itching) sounded highly consistent with a syndrome known as miliary dermatitis, which is caused by allergies to fleas. Was the reader by any chance using a flea preventative?

The reader responded quickly. He had, in fact, seen a few fleas on his cat. This confirmed the diagnosis. The reader stated that he was strongly opposed to flea preventatives because he didn’t want to apply chemicals to his pet.

I was taken aback by the man’s scientific illiteracy. He didn’t want to apply “chemicals” in the form of a flea preventative to his cat, but he wanted to use Neosporin (which is made of chemicals) to treat his cat’s scabs. Those scabs, by the way, were the result of his cat’s body’s response to the complex mixture of chemicals in flea saliva — and the man was perfectly happy to subject the cat to those chemicals which were clearly causing adverse effects in the cat.

Did the man even know what a chemical is? Did he realize that water is a chemical?

Perhaps he was only opposed to man-made or unnatural chemicals. But what makes natural chemicals so safe? Cobra venom is made of natural chemicals. Flea saliva is made of natural chemicals. The potent liver toxins in death cap mushrooms are natural chemicals.

Heck, if you want to talk about dangerous chemicals, I can think of a real doozy off the top of my head. Our world is contaminated — nay, saturated — with a chemical whose dangerous potential is phenomenal. The chemical, in its pure liquid form, can burn away a person’s body to the point that almost nothing remains. It potentiates fires and plays a significant role in the damage to DNA that leads to many cancers. It is an oxidizer so powerful that the very term “oxidize” was named for it. You’re sitting in a 21-percent solution of the chemical as you read this, and that’s a good thing — because if you or your cat went three minutes without oxygen you’d be dead.

So in my opinion fear of “chemicals” is totally fallacious. But I have digressed.

Is it safe to apply Neosporin on cats?

No, it is not. Nor is it legal. In a recent Catster post I discussed the fact that, in the United States, it is illegal to use any medication — prescription or over-the-counter — in a manner inconsistent with its labeling. Neosporin is not labeled for use in cats, so it is illegal to apply it to a cat.

The reason for this illegality, as best as I can tell, is that the FDA is a bureaucracy and as such its primary purpose is to perpetuate itself. It does this by making and enforcing rules, whether or not those rules make sense. But in the case of Neosporin and cats the rule actually does make sense.

The FDA is not going to kick open your door and arrest you if you put Neosporin on cats. But you still shouldn’t do it.

Here’s why: Neosporin and other triple antibiotics contain three active ingredients. They are neomycin, polymyxin B, and bacitracin. In some places similar “double antibiotics” such as Polysporin contain only polymyxin B and bacitracin.

Polymyxin B has been linked to anaphylaxis and death in cats.

The reactions are rare and have most frequently involved ophthalmic products (intended for use in the eyes). But any use of Polymyxin B in cats is a big no-no.

Regulatory and legal matters aside, it is almost invariably a bad idea to administer any human medication to a cat. I am aware of a case in which a woman administered Vicodin to her cat because the cat was limping. She did not realize that Vicodin contains acetaminophen, which is highly toxic to cats. The cat suffered liver failure.

Other owners have administered Tylenol (which also contains acetaminophen), Advil (Ibuprofen — toxic to the kidneys and gastrointestinal tract), or Aleve (naproxen — also toxic to the kidneys and gastrointestinal tract) to cats. Owners intending to administer Benadryl (generally safe) to their cats have accidentally given combination products containing acetaminophen or pseudoephedrine (neurotoxic to cats).

Cats are unique little creatures with highly unique metabolisms. Medications that are safe for people and dogs often are not safe for cats.

Self-medicating pets is generally a dangerous proposition. Although most cats won’t suffer reactions to polymyxin B, the potential adverse reactions are so serious that the medication just isn’t worth it — especially when one considers that in most cases it’s not very useful in cats.

I stand by my original suggestion to the reader. The chemicals in high quality flea preventatives are safer than those in Neosporin or in flea saliva.

Learn more about your cat with Catster:

• Weird Cat Facts: 8 Reasons Your Cat Likes to Lick You
• 10 Sounds That Cats Make — and What They Mean
• 8 Things to Try When Your Cat Won’t Eat

Got a question for Dr. Barchas? Ask our vet in the comments below and you might be featured in an upcoming column. (Note that if you have an emergency situation, please see your own vet immediately!)