Feline aggression-between cats or directed at humans-is, after inappropriate elimination and urine-marking behaviors, the second most common reason cats are seen by behavioral specialists. For diagnosis and treatment it is important to determine the motivation for the aggression. The more common causes for human-directed aggression in cats include play, fear, petting intolerance, and redirected aggression. Other causes include pain and maternal behavior. Sexually motivated and status related aggression are much more rare. Treatment includes a combination of behavioral modification, environmental modification, and, in some cases, medication.