Jen,
Wow..I didn't see this the other day. I am glad Biddy is on the mend. I wonder about Lucas, though. Is he on an anti-bi? Sometimes that can re-upset the tummy. I have had great success with Keopectate. I don't think it would harm a cat with normal bowels..like when you can't figure out who it is..but, maybe you should check with the vet. Sometimes an anti-diarrhal isn't a strong enough anti-spasmadic..good luck!