In both dogs and cats, trim only the end of the nail, at the point where it begins to curve downward. Cutting the quick is painful and will make Rover or Kitty bleed. If necessary, hold a gauze pad firmly to the nail until the bleeding stops. The quick is easy to see and avoid in white nails-it's the pink part. Always cut below the pink line.
Dark nails are trickier, though.
It's hard to tell where the quick is until you've cut it. So when trimming dark nails, be conservative. Go slowly and only trim the curved part of the nail. If you're new at trimming your pet's nails, watch your veterinarian or groomer do it first, and then let him or her talk you through it as you try it. With practice, both you and your four-legged friend will learn that nail trims really aren't that bad.