Cat's Tongue Hanging Out And Drooling. Can You Help?

My 4 year old cat had this problem.  He suddenly started drooling, had his mouth open and his tongue sticking out.  We took him to the vet and learned he had a upper respiratory infection and ulcers in his mouth.  He needed to be treated with antibiotics and was better in a few days.  It doesn't happen a lot, but cats can get sore throats and bacterial infections just like we do.

He is POISIONED
GO TO THE VET NOW OR HE CAN and probably will DIE!
I had the same thing happen. Hurry They will lick the toxins. Trust me call take to vet

It is hard to tell how serious this is without examining your cat.  If the groomer gave flea medication meant only for dogs than this is serious and your cat needs to be examined ASAP.  Some flea medication meant only for dogs can cause neurological signs and seizures in cats.
Cats can also get taste reactions from licking benign products off their coat.  This causes severe drooling and sometimes lethargy.  Give your cat some milk to drink; this removes the taste from his mouth, then bath the cat with a liquid dishwashing detergent (non the dishwasher products) so this problem is not repeated.  
If you have any concerns it is always safer to have your cat examined by a veterinarian.

Get him to the vet quickly! It is important, but feed it first