My cat who is 15 months old, every couple months for the last 6 months has been having problems with diaherrea. My cat is an indoor cat. My vet has checked her for worms, parasites, etc. Results came back negative. My vet thinks she has hairballs that is causing the problem. This last week, she started the diaherrea thing again. I gave her the Laxatone for 4 days straight (using a syringe because she does not like it). The Laxatone did not help. So, my vet had me give her a Pepto Bismol tablet to clear up the diaherrea. It did not work completely. Last night, she pucked up the biggest hairball I have ever seen. It must have been in her system for sometime. Now, my vet wants to check for Colitis. However, there is no blood in her stool. The diaherrea causes her to not use the litter box I guess because of the squirting and the sensation?? Has anyone out there had the same problem?