Electronic cigarettes are billed as healthier alternatives to the regular variety — for humans, that is. To our pets, they mean something very different.

Instead of tobacco, e-cigarettes contain a cartridge filled with a base liquid, flavoring and nicotine. It’s the nicotine that can pack a lethal punch.

An e-cigarette with a full cartridge can contain up to 36 milligrams of nicotine. While that’s a pittance for a person, doses of 20 milligrams of nicotine can be deadly to cats or small dogs. Even worse are the bottles of filler liquid, which can contain up to 1,080 milligrams of nicotine — more than enough to kill a big dog. And nicotine doesn’t have to be ingested to be dangerous — it can be absorbed through the skin if your pet walks through a spill.

You can keep your e-cigarettes, but keep them far, far away from curious creatures. The life you save could be your pet’s.