I have a part Russian Blue cat who, for some reason, just cannot seem to hold down his food unless I give him oily tuna. I've tried putting hairball ointment on his lips and on his paws, and even when I am successful at getting him to actually ingest the ointment rather than throwing it all around the house, it still seems to do little or no good. The cat cries because he is hungry, but he eats and then throws the food up. What can I do? Last time I brought him to the vet about this, the vet just gave me a tube of that ointment and said all will be fine. He can't seem to grasp that the ointment (a flavored vaseline product) just isn't doing the job.