Even though "EEEEEEWWWWWW"-post are helpful, the reason you should avoid it because it's an unnecessary risk. First of all, a mouse isn't the best food to begin with. Second of all, like stated before, you don't know what you are feeding the toad with. It might have some nasty diseases, but perhaps even more dangerous, there's always the risk of parasites and/or nasty worms which could easily become a real health risk.
Get rid of the mouse and buy a big nice B. dubia instead, if you want to give the frog a treat