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

it depends on the medicine. some topical treatments are meant to be absorbed into the bloodstream, others will create a layer of medicated oil that spreads over the skin.

fleas, especially, roam all over a dog’s body…..whereas a tick is more likely to be stationary.