From the Editors of The Daily Cat
Brushing is very important to help keep your cat's coat healthy and to limit the amount of hairballs due to self-grooming. Cats have very sensitive skin, though, so it's not unusual for them to react negatively to being brushed.
First, make sure you're using the right type of brush for your cat. If you have any doubts, ask your veterinarian or a professional groomer. Then, go over your grooming technique. There are parts of a cat's body that are very sensitive, such as the flanks, across the backbone, and the stomach. Don't start out brushing in a sensitive area. Begin by gently brushing in a spot that the cat enjoys, such as right behind the ears. Make your brushing technique an extension of petting. Just do a couple of strokes, offer your cat a treat or some praise, and then end the session.
Make each grooming session very short so it ends before the cat has time to realize what you've been doing. Gradually you can increase the time of the sessions as your kitty gets used to the procedure, but still keep them short. Whenever you have to brush in a more sensitive area, do one or two strokes, and then go back to a favorite spot, such as behind the head.
It's also important to watch your cat's body language. Before she tries to bite the brush, she may be giving off other signals to indicate that she's reaching her tolerance threshold. Signs of increased agitation can include tail-lashing, skin twitching, looking back at the brush, ears rotated back and shifting body position. When you see these signs, stop the grooming session.