If your ferret doesn't like the brand you bought, try another one.  Most
of ours turn up their noses at Petro-Malt, and the Marshall's brand.
They all seem to like Laxatone and Laxastat.
 
You can also give them unsweetened pineapple juice, however do not do
this unless directed to by the vet.  It is very acidic, and can damage
the stomach unless adequate countermeasures are taken.
 
[DA]
[Posted in FML issue 3645]