ELi5: How does my dog’s flea and tick prevention medication work on his entire body, when the only spots we rub it in on are some parts of his back?

Question

I am not talking about the pill type obviously, but the type that is like a small tube of oil that you rub in once a month. Instructions on these often state it goes on the dog’s back only.

Additionally, how do flea collars protect the dog’s entire body when it only goes around the neck?

In: Other

Answer 1

You do not rub it in. Some types absorb into the bloodstream and others create a coating over the skin.

Flea collars work by either emitting a gas to repel pests or by seeping into their skin .