Why is this dangerous?
Mothballs contain either naphthalene or paradichlorobenzene. Both cause oxidative damage to red blood cells, leading to anaemia, and naphthalene can also cause liver damage and seizures.
Cats are far more sensitive than dogs and can be poisoned by fumes alone in a closed cupboard or a sealed storage box.
Why speed matters
Delaying care significantly worsens outcomes. Some signs appear hours or days later, so "looks fine right now" is not a reason to wait.
Signs to watch for
- Vomiting, drooling, abdominal pain
- Weakness, lethargy, pale or yellow-tinged gums
- Brown or dark urine (red blood cell breakdown)
- Rapid breathing or breath that smells of mothballs
- Tremors, seizures, collapse in severe cases
What to do right now
- Treat as an emergency and go to the vet now — anaemia can develop over hours to days.
- Bring the package so the vet knows whether it is naphthalene or paradichlorobenzene.
- Do not induce vomiting unless instructed; these are volatile and easily inhaled.
- Air out the room and remove every mothball from the home; use cedar or lavender instead.
If your pet shows any of the signs above, go to the nearest emergency vet now and call ahead.
The step-by-step response, from the first minute to the vet visit, is in our Mothballs (Naphthalene, Paradichlorobenzene) emergency guide.