The bin tips over and your dog trots off with a tissue. Soon there is paper all across the room. For some dogs, tearing it is the fun part. The important question is whether your dog is shredding or swallowing.
If you suspect they swallowed a large amount, a paper towel, or something contaminated with medicine or chemicals, contact your veterinarian promptly. Vomiting, loss of appetite, abdominal pain, or trouble passing stool after swallowing an object needs urgent advice. Don't induce vomiting or wait for a blockage to become obvious.
Remove the easy prize
Use a lidded bin your dog cannot open or keep the bathroom door closed. Put used tissues away promptly, and don't chase your dog around the house for a harmless piece, that can turn theft into a game. If they stiffen or growl over an item, give space and ask a qualified behavior professional for a safe plan rather than prying it away.
Offer safe outlets for the urge to tear or investigate. Some dogs enjoy a supervised paper-filled box with treats scattered inside, but skip loose paper if your dog tends to swallow it. A food puzzle, scent game, or suitable chew may be a better fit. Reward them for choosing their own activity before the bin becomes interesting.
Notice when the shredding happens. If it is only while you are away and comes with barking, pacing, or escape attempts, separation-related distress may need attention. If it happens beside you after a dull afternoon, make their routine more interesting. Protecting the bin gives you time to learn the difference. If the shredding is an activity need rather than distress when left alone, the high-energy dog activities guide has more outlet ideas, keep swallowable tissues away
Sources: PetMD: Why Do Dogs Shred Paper Products?. ASPCA: Destructive Chewing.