One of my dogs, Annie, was on Slentrol before and did very well, losing 10#. Due to the fact, despite dietary changes, that she gained her weight back, the Vet decided to put her back on it for awhile (she is now 104#). Here's where my warning comes in. I got him from the Vets and gave her 2 daily doses when I discovered that she had vomited up her guts the second day. When I went to the box label (a Slentrol-issued prescription label) I knew something was wrong and checked the internet (Slentrol site) to see what her dosage SHOULD be. Based on .0045ml/body weight, she was prescribed more than 4 times what her dosage should be. Called Vet immediately and he was very concerned and told me to stop for 3 days. He looked at the history, all done neatly by Slentrol's prescription program and I saw the paperwork as well. Everything had been correct on her graph and history, EXCEPT this last prescription. I hope no damage was done, but EVERY OWNER must be aware to doublecheck the dosage themselves because obviously there is a gliche in the computer program of Slentrol given to veterinarians. Annie does have hyperthyroidism and the doctor says this is not a problem. She was really good on the weight she lost before.