Hello. Thanks for writing in.
How old is he?
How long has this been going on for?
Is there anything he could have gotten into (i.e.; chemical, plants, bugs, frogs, toads, lizards)?
If you look into his mouth, do you see any redness or sores on the tongue, gums, roof or back of the mouth?
Thanks for the information. It is most likely something he ate, such as a frog, toad, lizard, bug or plant. Some plants and certain toads (Bufo toads) can be very poisonous and cause a lot of other severe problems. Most of these ingestions will only cause some gastrointestinal upset and excessive salivation. In a case like this, I would try rinsing his mouth out with a little bit of water. A steady stream from a water hose for 1-2 minutes works best if he will tolerate it. Most cats won't last this long, so whatever you can do should help. Make sure his nose is pointed down so not to drown him. If the excessive salivation and restlessness continues, though, I would have your vet check him out ASAP. Some of these intoxications can cause more severe problems. Liver, kidney, pancreatic, gastric ulcer and inflammatory bowel disease issues can cause excessive salivation, but it is usually not so acute. Please let me know if you have any other questions. Hope this helps.