[GuinnessStout]

I used to use it but I have never had flea issues, but after trading vets to one that is known for being great in our area but very very expensive he told me that it does not kill fleas till they bite the pup so he could still get the dieases and it is a toxin that stays flowing thru their system and since yorkies are known for liver issues it really was not in my best interest to risk my fur child's health.