I found some white round pills that have the marking on one side of YSP and 173. Does anybody know what they are?

Thanks,

MK

You can identify it here. It is a very serious drug and if it is not yours should be disposed of properly.

Kinney Drugs | Drug IDentifier

It's the generic form of Ambien.

In any case, as said above, if it's not yours and wasn't prescribed you could have bad side effects if it's "not right for you"

Zolpidem - Wikipedia, the free encyclopedia