Not sure what “a lot” means but there’s some animal veterinary stuff that we buy every 6 weeks or so because… well… shit’s expensive and not always easy to find locally. It winds up being either Amazon or Chewie that has the stuff in stock and at prices (even with shipping) that are manageable with our budget.
Most of the stuff is in sealed and tamper evident containers, so at the very least, we’d know something was up before trying to use anything.