Human nail clippers are safe to use on smaller dog breeds as it's easier to control the process. Use clippers specifically designed to trim the nails on larger dog breeds. Avoid accidentally cutting the blood vessel in a dog's claws, called the quick, as they will bleed if cut.
If a dog's quick is accidentally cut, use a paper towel and apply gentle pressure to control the bleeding. Then cover the wound with styptic powder, an astringent that constricts blood vessels and tissue, and prevent the animal from licking it. It takes approximately 5 minutes for styptic powder to work.