For those asking the question.. Petromalt is a feline hairball remedy. Basically like other hairball remedies it consists of white ptroleum and molasses. It is recommended that the hairball remedy such as Petromalt or Laxatone or their equivalent be administered once weekly(1/2 " to 1" ) and every or every other day during shedding season (Spring and Fall). The hairball remedies are swallowed and coat any hair or other foreign debris in the ferrets stomach and assists in passing the aforementioned residue through the digestive tract. It is very IMPORTANT to get your ferrets into this routine. They preen themselves just like a cat and though you are not aware do indeed ingest hair. Unlike the cat seldom are ferrets able to cough up a hairball. .. rather it sits in the stomach and knots up getting bigger and bigger. IF you realize there is a problem and you take it to the vet... an xray would be required to diagnose the problem and possibly the vet could help with evacuation of the hairball if it has gone beyond the quick fix of hairball remedy... if not it becomes a matter of SURGICALLY REMOVING the obstruction caused by the hairball. All this can be prevented with routine maintenance--- administering hairball remedy on a regular basis... A VERY worthwhile investment Happy ferreting [Posted in FML issue 1463]