How big was the piece?
 
If it was pretty small, give 1/2 inch of laxatone or petromalt and watch
very carefully.  If it was a big piece, think about going into the vet
right away if you are sure it was ingested.  Unfortunately styro won't
show up on a x-ray.  If your kid paws at his/mouth repeatedly or has thin
stringy stools take the fert into the vet immediately.  (S)he might need
surgery.
 
Hoping it turns out ok,
Matthew in CO.
[Posted in FML issue 3455]