Mothballs are insecticides intended to kill clothes moths and other fabric pests. Controlled by the Environmental Protection Agency, they are illegal to use for any purpose or by any method that isn’t specified on the label directions. This article explores if mothballs are effective wildlife deterrents for mice, snakes, bats, and other creatures, and highlights important health factors based on existing research.

History of Mothballs

Before modern air conditioning and heating systems were commonplace, households sought out natural airflow to regulate indoor temperatures, which brought with it the invasion of pests eager to eat homeowners’ favorite clothing. In response, mothballs became the first line of defense, a key element of clothing care and preservation.

With synthetic materials like nylon and polyester now blended with natural fibers like cotton, moths rarely seek out clothing as a food source. Nonetheless, there are many advertised uses for mothballs in the house and outdoor areas for wildlife control, many of which are considered dangerous or illegal.

How Mothballs Work

Mothballs are round discs of solid pesticides with the active ingredient naphthalene, camphor, paradichlorobenzene (dichlorobenzene). These solid discs release vapors that are toxic to moths and moth larvae, eliminating them or deterring them from the area. However, to be effective for pest management, mothballs must be placed in airtight containers where moths are exposed to high concentrations of vapors.

Mothballs as a Wildlife Repellent

Mothballs are frequently suggested as wildlife deterrents in both indoor and outdoor areas. These solutions are ineffective, dangerous to humans and pets, and illegal in some cases.  


Mothballs are commonly made of naphthalene or paradichlorobenzene, both of which are toxic to humans and have detrimental health effects. Accidental mothballingestion is common in children. Fumes from naphthalene mothballs can escape into the air and can cause respiratory problems. High levels of fumes can accumulate in closed areas, and improper use of mothballs can lead to long-term exposures to people and pets. Medical issues as a result of mothball naphthalene poisoning include hemolytic anemia, methemoglobinemia,  and in rare cases, kidney damage.

For these reasons, mothballs should not be stored in closets, crawl spaces, attics, basements, storage chests, garment bags, or other spaces excluding airtight containers.


Mothballs are occasionally thrown in gardens and lawns to keep away pets and other animals. However, mothballs are ineffective in repelling wildlife in outdoor areas such as rats, mice, squirrels, bats, snakes, or other wildlife.  Mothballs may contaminate soil and water and their use as animal repellants is not appropriate and can be illegal.

Do Mothballs Ward Off Snakes?

Mothballs don’t repel snakes. As snakes are attracted to areas that provide cover and shelter, homeowners should remove log or trash piles close to the home and maintain grass or other vegetation to make the area less appealing.

Will Mothballs Repel Mice & Rats?

Mothballs contain naphthalene, but the small quantity in mothballs is insufficient to effectively deter rats or mice , and the smell rapidly dissipates. The smell can be a deterrent in large enough quantities, but will not prevent rodent infestation, on top of health risks.

Bats and Mothballs

Unfortunately, there are no magical products to repel bats, including mothballs. Similar to mice, naphthalene is an annoyance to pests, but not enough to prevent the species from occupying your living space.

Groundhogs and Mothballs

Filling a groundhog hole with mothballs is not effective, and increases the chance that the groundhog will simply create another den nearby until the smell dissipates, which happens rapidly. Groundhog-proof fencing or removal services are the only effective, guaranteed solutions.

Mothballs, Chipmunks and Squirrels

While chipmunks and squirrels dislike the smell of mothballs, mothballs are a less effective option relative to trapping and removal services. Mothballs are considered an inhumane alternative as chipmunks and squirrels may die after consuming. Lastly, the use of mothballs to deter chipmunks and squirrels may be illegal depending on your locality and is bad for the environment.

Do Repellents Work?

Natural repellents like predator urine, citrus ammonia, and mothballs have low effectiveness as deterrents.

Instead of using ineffective mothball solutions to deter mice or other wildlife species, contact Critter Control technicians who can tailor permanent solutions for your wildlife problem. Mothballs are ineffective deterrents of wildlife, and most importantly pose health risks to the inhabitants of a home.