Hello I am Dr. Joey. Thanks for trusting me to help you and your pet today. I am a licensed veterinarian with over 16 years of experience. I look forward to working with you.
This poor girl. With diarrhea persisting this long does suggest there is probably something significant going on with her digestive tract. The bad news is diarrhea is very nonspecific to indicate one particular problem. As far as underlying cause it could be anything from food allergy to intestinal parasites to inflammatory bowel disease to pancreatitis to liver problem to endocrine disease (hyperthyroidism or diabetes) to cancer and the list continues.
After this period of time the absolute best next step for Cece is to be seen by her veterinarian for some testing. She really needs some lab work (CBC, chemistry profile, urine check, thyroid screen and stool evaluation). If this is entirely normal then radiographs (X-rays) are indicated to look at her digestive tract.
There is not a lot you can do at home. You are certainly welcome to try a diet change, but I would suspect after this period of time you have already tried this. I do not think it will make a lot of difference. You can give some antidiarrheal medication such as kaopectate (no more than 0.5 ml; 1 ml = 1 cc) every 12 hours but this would only be a temporary solution and is putting a band-aid on the problem but not fixing it. It also doesn't work that well in cats.
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