Originally Posted by Cerridwen

I would recommend feeding raw only, at least in then beginning. So no biscuits. Do it as simple as possible. Try minced lamb with some carrot puree (homemade) for a week and see if something happens with the poo. That's always what I recommend as a start. If it works and the diarrhoea goes away the cat should eat this lamb diet for another week or two in order to let the intestines heal, but you'll need to start adding a few minerals, vitaminas and taurine in this stage. But you can go for a week without any supplements.

If you for some reason don't feel comfortable with raw mince or if the cat won't eat it raw you can cook it slightly.