Moth Repellent Product Poisonings in Cats

Did you know that mothballs can be toxic to pets? Commonly found in closets around the world, mothballs are typically used to repel moths and prevent them from destroying clothing. As little as one mothball can potentially result in significant illness in a small dog or an average-sized cat. Mothballs usually contain naphthalene or paradichlorobenzene and can be formulated into cakes, balls, or flakes.

According to the ASPCA Animal Poison Control Center, approximately four-dozen cases involving exposure to mothball products were reported in 2005. Circumstances of exposure can vary, from ingestions or inhalation to contact with skin. Cats are generally less commonly involved in mothball toxicities, perhaps due to their keen sense of smell and very discriminating palates.

In addition to gastrointestinal irritation and lethargy, mothballs containing naphthalene have the potential to cause serious effects such as liver, kidney and blood cell damage, cerebral edema (swelling of the brain), coma and even death. Depending on the route of exposure, clinical signs can develop within minutes (such as with inhalation) to hours or even several days (typically with long-term low dose exposures).

Mothballs containing paradichlorobenzene are generally considered to be somewhat less toxic than naphthalene. However, gastrointestinal upset and potentially even neurologic effects are possible if large enough quantities are involved in the exposure.

What to Watch For


The diagnosis is generally based on physical exam findings and a history of access or exposure to mothballs.
Blood tests are often done to determine the overall health and to establish a base line of organ function. Repeat blood chemistries may be recommended to monitor for liver or kidney damage and effectiveness of treatment.


Treatment is often symptomatic and supportive, depending on the clinical signs present and condition of the pet.


The prognosis for mothball ingestion depends on the amount ingested, the size and age of the pet, general health of the pet, and the severity of clinical signs present. Pets with mild signs usually respond to symptomatic therapy. Pets with more severe signs such as liver disease or anemia have a more guarded prognosis.

Home Care and Prevention

There is no home care for mothball toxicity. Veterinary care is strongly recommended to prevent and manage clinical effects associated with toxicity. If you suspect that your pet may have been exposed to a mothball product, contact your local veterinarian or the ASPCA Animal Poison Control Center (1-888-426-4435) for immediate assistance.
While recovering from toxicity, feed your pet often and encourage him or her to eat well. Watch for failure to eat, vomiting, seizures or other abnormalities.

The best approach in avoiding an accidental mothball poisoning is to prevent exposure; never use mothballs in areas to which pets have access, and store unused mothballs in a secure location above countertop level.

For more information on mothballs or other potentially toxic substances, visit