giving a probiotic like Fortiflora. When Ollie had his PU surgery, he was on so many antibiotics, he had the same poo. It wouldn't stop. Got him on the Fortiflora and it took awhile, but his finally got firmer. I know they do really help, with inflammation and all too because of the good bacteria in it. Just sprinkle in morning or evening food once a day. Most cats love it. Hope Jonathan feels better soon. May want to take to vet if it keeps up.