Stopping your dog from chasing your cat can be done in many ways but takes time and patience. Positive reinforcement, redirecting their behavior, and teaching your dog basic commands can cut down their prey behavior. When a dog becomes fixated on a cat, it becomes obsessed over it. From just growling to barking, it will lead to constant lunging and chasing. Keeping them entertained can give your cat a safe space to relax. If none of these works, try to introduce them to each other all over again.