will these pills hurt the engin and do they work.
No and no.
And also, no.
No, they will not hurt the engin (or the engine). They will not work for you in terms of improving gas mileage, but they definitely work in terms of enriching the charlatan who is marketing them to gullible consumers.
Whatever they’re supposed to do… they don’t.
When asking a question of this nature, it’s generally good to provide us with a link so we can see what you’re talking about.
Whatever they are, they definitely can improve mileage. Balance one on the edge of your dash and drive such that it never falls off. But don’t put them in your tank. They’ll not help there.