Mothballs are one of the oldest rat remedies going, passed down like family wisdom. The problem is that the wisdom is mostly wrong — and in this case, the popular fix is genuinely risky. Here is the honest picture.
Why people think they work
Mothballs release naphthalene, a strong-smelling chemical that rats do dislike. In theory, fill a space with enough of it and rats stay away.
Why they don't
The catch is in the word "enough." The concentration of naphthalene needed to actually drive rats out is far higher than is safe to have in a home. At the small amounts that are safe, a determined rat simply tolerates the smell to reach food or shelter. So you are left with a faint odour that does not solve the problem.
And they are a real hazard
Naphthalene is toxic if inhaled in quantity or swallowed — a genuine danger around children and pets, who may mistake mothballs for sweets. The dose that might bother a rat is exactly the dose that becomes unsafe for your family. That trade-off alone rules them out.
What to do instead
- Remove the food — sealed containers, no crumbs, covered bins.
- Remove the shelter — declutter and seal gaps larger than 2 cm.
- Add a safe, lasting deterrent — one that does not depend on toxic fumes.
The EchoRepel Ultrasonic Rat Repellent keeps problem areas uncomfortable for rats using ultrasonic sound — no chemicals, no fumes, safe to run around people and pets. For more on scent-based remedies, see what smells do rats hate.