Depending on where the bleeding is coming out from and what causes it, you may need to see a vet. Bleeding that occurs after the claws have been cut due to a blood vessel injury is treated by pressing a cotton pad against the paw for a few minutes.  You should do the same if the animals injure one another with their claws. But urinary tract bleeding (uterus bleeding) or blood in the urine isn’t something you can treat yourself at home. It would be best if you took your pet to see the vet.