how will I know if it was a poisoned one and will it matter?

Hi guest
of course it will matter if your pup starts to vomit everywhere. question is where was the mouse and why would you think it was poisoned?
If you're seriously worries call your local vet for some quick phone advice and he'll tell you what to keep an eye out for it it was poisoned
can't be too careful with puppies - they can eat loads of stuff but they can be quite delicate too.
hope this helps

Hi guest, if you believe the mouse was poisoned & your pup swallowed it I would take it the vet asap. The poison will make the pup very ill with vomiting/diarrhea/salivating/fits & the earlier he gets to the vet the better. If the mouse wasn`t poisoned your pup should be OK or he may even sick it back up with no probs. Afraid I can`t tell you how you would know if the mouse was poisoned unless you put the poison down for it or know some one who has.
Christine, Spain.