Our dog has bitten me and attacks our other dogs. He started having seizures and is taking medication. I'm wondering if his behavior is training related or medical related. Please help!

I happened across your website today while doing a search on aggressive dog behavior. I have a Blue Heeler, and have raised him since he was 6 weeks old. He is now approaching 9 years.

When he was a puppy, I was able to teach him to sit, shake, etc, and he listens fairly well when we are outside playing if it's just him and I. There has always been one other dog in our home, but within the last three years, my son moved his dog in (due to apartment living), and my daughter moved home with her St. Bernard/Collie mix. We also have a Miniature Pinscher.

Two years ago, the Heeler began exhibiting some aggressive behavior. He attacked me one evening (bit through a heavy Carhartt coat), but I assumed it was because it was dark and I startled him. Now, he attacks the Min Pin on a regular basis (grabs him by the throat), and also goes after the St. Bernard. In addition, he began having seizures, and is taking medication.

I love this dog but find myself being intimidated on a regular basis. When I leave the house, I have to put the Min Pin & St. Bernard in a room that the Heeler can't get into, because I am afraid that I may come to home to a massacre one day. I have tried to put the Heeler in another room, but he won't have any of it. At night, he frequently gets me up to go outside, possibly due to the meds, but when I let him back in the house and head for my room, he sometimes runs at me (while my back is turned) and bites at me hard!! He manages to work his way between me and the hallway, and even attempts to force me to back up. If I won't, he will on occasion lunge at me.

Do you believe his behavior can be changed with training, or might there be some medical issues that would inhibit anything from helping??? I'm at a loss. Any advice is welcome and appreciated.