Toxicity to pets

Mothballs are pesticides that slowly release a gas vapor to kill and repel moths (and their larvae) and other insects. Mothballs are also used to repel snakes, mice, and other animals, though this use is not recommended and can be harmful to pets, children, and the environment. Mothballs come in cakes, scales, powder, balls, cubes, spheres, and flakes and may contain the insecticides naphthalene, paradi-chlorobenzene (PDB), or occasionally camphor. Older mothballs most commonly contain naphthalene. Due to concern for naphthalene’s flammability and toxicity, most modern mothballs now contain PDB instead.

The chemicals in mothballs can be inhaled, absorbed through the skin, or absorbed through the stomach and intestines. Cats are more sensitive to the toxic effects of mothballs, but dogs are more likely to ingest mothballs. Naphthalene mothballs, or old-fashioned mothballs, are considered the most toxic type of mothball. Modern PDB mothballs are less toxic but still can cause illness, especially when ingested. Clinical signs of mothball poisoning include vomiting, mothball-scented breath, pale or brown gums, weakness or lethargy, difficulty breathing, tremors, seizures, and organ failure (e.g., liver, kidneys).

If you suspect your dog or cat ingested mothballs, contact your veterinarian or Pet Poison Helpline® immediately for life-saving treatment advice.

Content written by: Dr. Charlotte Flint, Pet Poison Helpline®