I am sorry about your dogs...My wife and I just lost our dog (Boston Terrier) at one year old from the same symptoms. Unexplainable internal bleeding. Autopsy showed nothing. Were you using REVOLUTION on the dogs for fleas etc...My local breeders are telling me that REVOLUTION is causing many cases of spontaneous internal bleeding in many breeds of dogs and that Pfizer is reimbursing pet owners for purchase price and vet costs. An admission of guilt, if you ask me.