Gluten free aspirin?

I bought a small plastic container of aspirin at the drug store today. No problem, I do this a couple of times a year.

But for the first time, I noticed (in fairly large letters) the words “Gluten Free”. Which made me wonder – would aspirin normally have gluten in it as an ingredient? Why are the making such a big thing of this?

Or is the drug store (it was their house brand) capitalizing on the “gluten free” craze and making a big think out of something that the aspirin never had in it, in the first place?