Strict for medical bills, proof for the rest
Pennsylvania's Dog Law, 3 P.S. 459-502(b)(1), requires the owner or keeper to pay fully for the victim's medical treatment from an attacking or biting dog. To recover other damages, you must show negligence or that the dog was previously classified as dangerous.
The dangerous-dog statute, 3 P.S. 459-502-A, covers dogs that inflict severe injury without provocation. Dangerous dog owners must carry at least $50,000 of liability insurance.