Sorry, this is long and also contains descriptions of cat poop so please don’t read if you’re not in the mood for reading about my cat’s dodgy guts.
One of our cats has had the squits for over a year now. When it first started the vet could feel a lump in her intestine and diagnosed Inflammatory Bowel Disease. Since then she’s been on varying doses of steroids, Famotidine (reduces stomach acid), had a few courses of antibiotics and tried a course of an immune supressing drug called Atopica.
We tried her on a prescribed diet (can’t remember the name unfortunately) by slowly mixing it with her normal food, but she threw it up everywhere and seemed very unwell 
She was painfully skinny when it started but has now put on weight. The lump has all but disappeared, but sadly the squits have not. She does a poo at least 4 times a day and this varies from cow pat consistency to liquid. It stinks to high heaven and we are going through a bag of cat litter per day. The vet has once again taken poo samples and we’re waiting for the results to see if a different type of antibiotic might help. They’ve also taken blood again to make sure the long term steroid use isn’t doing any harm. She seems generally happy in herself, the vet is unconcerned about her general health apart from the poo issue.
Has anyone experienced anything similar? Do you have any recommendations for diet or any other supplement that might help?