Debbie--
One thing I've also seen in one of my ferrets that vomitted maybe once
every 2-3 weeks at first: Insulinoma.  This was her earliest symptom.  I'd
recommend watching a ferret with occasional unexplained vomitting for other
symptoms of insulinoma and including a glucose check in the diagnostic
process of discovering what ails the ferret.  None of the other ferrets
I've owned ever developed infrequent but recurring vomitting, so I have to
think it would be a problem worth investigating.
 
Debra
[Posted in FML issue 2809]