My cat pulls out its fur..?

Your cat could have allergies which you can have it tested for. You can draw bloodwork to rule out any health problem. It is not normal for a dog to pull out it's fur. It could be stress which your doctor could prescribe something for. Try keeping a journal of when you see it happening, what time of day or night, how often, what area he pulls from, what the situation is in the house at the time. These things can play a factor. Your vet should offer solutions to finding out the reason for your dog pulling out it's fur. If he isn't proactive about it I would consider another vet.