My cats..

[CultureJunky]

Yeah Laura is right, it could be something simple going around, like an upset stomach. It could also be a coincidence like furballs or just random. My cat Jack is sick quite often, furballs and bits of grass mainly. I think some cats have sensitive stomachs and need a special diet. Such as dry sensitive food to help regulate everything.
As long as they are healthy, have healthy eyes (no third eyelid showing) drink plenty and have a healthy appetite I don't think it'd be too much to worry about. If they start to get mushy watery stools though perhaps they could do with a check over. I hope that helps, our animals are sometimes a mystery to us I know

[catmandu]

That Sounds As Though Theres A Bad Virus Going Through Your Vets Office. It Could Be Someone Bringing A Sick Cat In, And The Germs Spreading That Way.
I Would Raise Hell And Make Sure Your Vet Gives You Free Medicines And Perhaps You Should Report That Clinic To The Vet Association.
We Hope That Your Cats Are Better Soon , And Have No Lingering Side Effects.