Hello, I'm Dr. Deb and will do my best to help you today.
I'm sorry that Ebony is producing excessive saliva.
Unfortunately, there's not just one reason shy she might be doing this; this could be several possible explanations:
1. Problems in the mouth such as an infected tooth, ulcers, abscesses, foreign body, even cancer, I’m sad to say given her age. It is possible that a good oral exam will reveal the problem or sedation may be necessary to adequately examine the mouth.
2. Nausea for any reason. Systemic diseases such as kidney disease or inflammatory bowel disease can cause cats to feel nauseous. Blood work might be suggested if this is suspected although inflammatory bowel disease is only diagnosed with a biopsy (understandably something thatmost owners are reluctant to have done).
3. Ingestion of any noxious substance that they might have groomed off of their bodies (such as flea/tick products) or anything unpleasant tasting that they might have licked.
4. Early upper respiratory infection or Calicivirus. This virus can attack the mucous membranes in the mouth and create ulcers on the hard palate and tongue which are quite painful. Typically, these patients are also sneezing or have an eye and/or nasal discharge.
5. Spontaneous. In some cats, we can’t find an explanation for their drooling and they will spontaneously stop and we won’t have had any idea as to why they started in the first place.
On the off chance that nausea may be playing a role, over the counter human Pepcid AC (Famotidine) can be given at a dose of ¼ of a 10 mg tablet twice a day.
I wouldn't necessarily consider this to be an ER type of situation but if she's still hypersalivating tomorrow and the Pepcid AC doesn't appear to be helpful, then a vet visit might be prudent.
I hope this helps. Deb