Squirrel bites can be dangerous, not because they are poisonous, but because they often carry germs of serious diseases. Some of these infectious diseases include Rabies, Lyme, etc. Hence, if you get bitten by a squirrel, seek medical attention as soon as possible.  Especially if the squirrel that bit you had foaming at its mouth and seemed weak, there’s a high chance that it was infected with rabies.