You find a torn box on the floor. If your dog only shredded it, that is one problem, if they swallowed pieces, the safety question changes. Paper can contain staples, tape, ink, glue, or food residue, and large amounts or packaging can cause a blockage. If you know they swallowed a substantial amount or any sharp or toxic material, call your veterinarian with the details rather than waiting for symptoms. Vomiting, abdominal pain, poor appetite, or lethargy call for urgent advice.
Repeated eating of non-food items is called pica and can have behavioral or medical causes. Ask your veterinarian to assess a persistent pattern, even if your dog otherwise seems normal. Bring a note of what they eat, when it happens, and whether it occurs only when nobody is home.
Stop rehearsing the behavior
Store mail, boxes, tissues, and wrappers out of reach. Empty bins into a secure container. Supervise access to craft or packing areas. If you catch your dog with a piece, do not chase them or pull an item from a tense dog's mouth. Invite a voluntary swap for a safe, higher-value reward if you can do so without risk, and seek professional help if the dog guards stolen objects.
Provide appropriate chewing and food puzzles that suit your dog, then teach "leave it" and "drop" with harmless practice items. Training does not make a swallowed staple safe, management and veterinary assessment come first.
Sources: VCA Animal Hospitals: Pica in Dogs. VCA Animal Hospitals: Ingestion of Foreign Bodies in Dogs.