Hi Elizabeth,
As far as the diarrhea goes, there is a probiotic called S. Boularddi. I use the brand Florastor that you can get at a CVS. There are other brands that are cheaper and that you can get online. I am familiar with the Florastor brand. It can be sprinkled into the food without detection from the kitty.
For a therpuetic dose, the instructions are give 1/2 the capsule twice a day. Do until the diarrhea stops then do a maintenance dose of 1/4 of the capsule twice a day for 3 more days.
If diarrhea is really bad, more than once a day the below is an Emergency Stop Diarrhea:
Give one-quarter of the 250mg / 5 billion CFU capsule every two hours or so. Many cats accept it when mixed into finely ground poached chicken breast / turkey breast / pork loin or meat-only baby food. (Beech Nut, Goya, and Gerber list “meat” and broth or gravy as ingredients. These are fine, they are referring to the water used to cook the meat, and they contain no spices). If your cat does not like the taste of the probiotic, you can syringe after mixing with water. If you are not experienced syringing liquids into your cat, you can use empty #3 gel capsules. Simply fill 10 to 20 of these by transferring the S boulardii from the larger capsules into the smaller ones. These are a size easy to pill your cat. Pill your cat with one #3 capsule filled with S boulardii every two hours or so.
The above information is from wwwfoodfurlife website. There is tons of cat health information on their site. They also on the below link talk about the use of Slippery Elm Bark which is helpful too for diarrhea, constipation, and nausea.
http://www.foodfurlife.com/my-cat-has-diarrhea---what-do-i-do.html
