Are Mothballs Toxic to Dogs? Symptoms, Doses & Emergency...
Are mothballs toxic to dogs? Yes — both naphthalene and paradichlorobenzene mothballs are dangerous. Learn toxic doses, symptoms, and what to do if...
Mothballs are small, deceptively candy-like pesticide pellets that many households keep in storage closets, attics, and basements. Their round shape and strong odor can attract curious dogs, and the consequences of ingestion range from severe gastrointestinal distress to life-threatening organ failure. Understanding exactly why mothballs are dangerous, how much constitutes a toxic dose, and what to do in the critical first minutes after ingestion can mean the difference between a full recovery and a devastating outcome.
Are Mothballs Poisonous to Dogs? The Toxic Compounds Explained
Yes — mothballs are highly toxic to dogs. The danger comes from the active pesticide ingredients, which vary by product. In the United States, mothballs sold for consumer use contain one of two primary toxic compounds:
| Compound | Toxicity Level | Key Characteristics |
|---|---|---|
| Naphthalene | Moderate to High | Older formulation; strong chemical odor; causes hemolytic anemia (red blood cell destruction), liver damage, and seizures. Floats in water. |
| Paradichlorobenzene (PDB / 1,4-dichlorobenzene) | Moderate | More common in modern products; causes liver and kidney damage, neurological symptoms. Sinks in water. |
A third compound, camphor, appears in some imported or novelty mothball products and moth repellent sachets. While less commonly encountered in the U.S. market, camphor is also toxic to dogs and causes seizures at relatively low doses.
According to the ASPCA Animal Poison Control Center, mothball exposures consistently rank among the top household product calls they receive each year. The Merck Veterinary Manual notes that both naphthalene and paradichlorobenzene are readily absorbed through the gastrointestinal tract, and clinical signs can develop rapidly.
The critical problem: mothballs dissolve slowly, meaning a dog that swallows one whole may not show symptoms immediately — but the toxin is continuously releasing into their system over hours.
How Much Mothball Can Kill a Dog? Toxic Dose Thresholds
Toxicity depends on the compound, the dog's body weight, and individual sensitivity. Here are the established thresholds veterinary toxicologists use:
| Compound | Toxic Dose | Lethal Dose (Estimated) | Practical Translation |
|---|---|---|---|
| Naphthalene | ~30–50 mg/kg body weight | ~400 mg/kg (severe cases reported lower) | A single standard mothball contains approximately 2,000–2,700 mg of naphthalene. For a 20 lb (9 kg) dog, one mothball delivers ~222–300 mg/kg — already in the severe toxicity to potentially lethal range. |
| Paradichlorobenzene (PDB) | ~100–200 mg/kg body weight | ~500–750 mg/kg | A standard PDB mothball contains approximately 2,500–3,000 mg. For a 20 lb (9 kg) dog, one mothball delivers ~278–333 mg/kg — well into the toxic range. |
| Camphor | ~50–100 mg/kg body weight | ~200 mg/kg | Camphor-containing products vary widely in concentration. Even small sachets can contain dangerous amounts for small dogs. |
Mothball Poisoning Symptoms in Dogs: A Timeline
Understanding the symptom timeline helps you recognize poisoning early and communicate effectively with your veterinarian. Mothball toxicity does not always present instantly — the slow dissolution of the pellet in the stomach can delay some signs.
Within 30 Minutes to 2 Hours (Early Stage)
- Vomiting — often the first sign; may contain mothball fragments with a strong chemical odor
- Excessive drooling (hypersalivation) — due to oral and gastric irritation
- Abdominal pain — dog may hunch, whine, or resist being touched around the belly
- Lethargy or restlessness — dog may pace or appear unusually subdued
- Mothball odor on breath — a distinctive chemical smell is a strong indicator of ingestion
Within 2 to 12 Hours (Progressive Stage)
- Diarrhea — may be bloody in severe cases
- Tremors or muscle twitching — especially with naphthalene and camphor toxicity
- Ataxia (uncoordinated movement) — stumbling, difficulty walking
- Increased respiratory rate — rapid or labored breathing
- Pale or brownish gums — a critical sign of methemoglobinemia (blood oxygen disruption), particularly with naphthalene
Within 12 to 72 Hours (Severe / Late Stage)
- Seizures — generalized or focal; more common with naphthalene and camphor
- Hemolytic anemia — red blood cell destruction causing weakness, jaundice (yellow gums/eyes), dark urine (naphthalene-specific)
- Hepatotoxicity (liver damage) — elevated liver enzymes, jaundice, clotting disorders (both compounds, especially PDB)
- Nephrotoxicity (kidney damage) — decreased urine output, elevated BUN/creatinine (PDB)
- Coma and death — in untreated or severely poisoned dogs
• ASPCA Animal Poison Control: (888) 426-4435 — available 24/7, consultation fee applies
• Pet Poison Helpline: (855) 764-7661 — available 24/7, consultation fee applies
Both services can advise you and your veterinarian on specific treatment protocols based on the compound ingested and your dog's weight.
What to Do If Your Dog Ate a Mothball: Immediate Action Steps
- Remove any remaining mothball material from your dog's mouth. Wear gloves if possible. Check for fragments in the cheeks or under the tongue. Place any recovered pieces in a sealed bag — your vet will want to identify the compound.
- Do NOT induce vomiting unless specifically instructed by a veterinarian or poison control specialist. Mothball compounds are volatile hydrocarbons. If a dog vomits and aspirates (inhales) the material into the lungs, it can cause a potentially fatal chemical pneumonia that is harder to treat than the original ingestion. This is why professional guidance is essential before any home intervention.
- Call your veterinarian or ASPCA Poison Control at (888) 426-4435 immediately. Have the following information ready:
- Your dog's breed, age, and exact weight
- The mothball brand and active ingredient (check the packaging — look for "naphthalene," "paradichlorobenzene," or "camphor")
- How many mothballs were potentially ingested
- Approximate time of ingestion
- Any symptoms already observed
- Transport your dog to the nearest veterinary clinic or emergency animal hospital. If your regular vet is closed, locate the nearest 24-hour emergency facility. Time is critical — early decontamination significantly improves prognosis.
- Bring the mothball packaging (or a photo of it) and any recovered fragments to the clinic. This allows the veterinary team to confirm the exact compound and calculate precise toxicity risk.
Veterinary Treatment for Mothball Poisoning: What to Expect
Once at the clinic, your veterinary team will move quickly. Here is a realistic picture of what treatment involves and what it may cost:
Diagnostic Workup
- Complete blood count (CBC) — checks for anemia, particularly hemolytic anemia from naphthalene ($80–$150)
- Blood chemistry panel — assesses liver enzymes (ALT, AST, ALP), kidney values (BUN, creatinine), and electrolytes ($100–$200)
- Methemoglobin level — specific test for naphthalene-induced blood oxygen disruption ($50–$100)
- Urinalysis — evaluates kidney function and checks for hemoglobinuria ($40–$80)
- Coagulation profile — if liver damage is suspected ($80–$150)
Treatment Protocol
Treatment varies based on the compound, time since ingestion, and severity of symptoms:
- Emesis (induced vomiting) — performed at the clinic using apomorphine injection, only if the dog is alert, not seizuring, and ingestion was recent (within 1–2 hours). The vet controls the environment to minimize aspiration risk. ($50–$100)
- Activated charcoal — administered orally to bind remaining toxin in the GI tract. Often given with a cathartic like sorbitol to speed passage. May require multiple doses over 24–48 hours. ($30–$75 per dose)
- IV fluid therapy — critical for supporting kidney function, flushing toxins, and correcting dehydration. Typically 24–72 hours of hospitalization. ($200–$600 per day)
- Anti-seizure medication — diazepam or levetiracetam if tremors or seizures are present ($50–$150)
- Liver protectants — N-acetylcysteine (NAC), S-adenosylmethionine (SAMe), or silymarin for hepatotoxicity ($40–$120)
- Blood transfusion — may be necessary in severe hemolytic anemia cases from naphthalene poisoning ($500–$1,500)
- Methylene blue — specific antidote for methemoglobinemia caused by naphthalene ($30–$80)
• Mild exposure (early presentation, no severe symptoms): $500–$1,500
• Moderate poisoning (hospitalization 24–48 hours, IV fluids, monitoring): $1,500–$4,000
• Severe poisoning (seizures, hemolytic anemia, blood transfusion, extended ICU): $4,000–$10,000+
Pet insurance with accident/illness coverage typically covers poisoning treatment. Check your policy's annual limits.
Prognosis and Survival
Will your dog survive mothball poisoning? The prognosis depends heavily on three factors: how quickly treatment begins, the amount ingested relative to body weight, and the specific compound involved.
- Early treatment (within 1–2 hours of ingestion), mild exposure: Good to excellent prognosis. Most dogs recover fully with appropriate decontamination and supportive care within 24–72 hours.
- Delayed treatment, moderate exposure: Guarded prognosis. Liver and kidney damage may develop but can often be managed with aggressive supportive therapy over several days.
- Severe poisoning (seizures, hemolytic anemia, organ failure): Poor to guarded prognosis. Dogs with significant hemolytic anemia from naphthalene or hepatic necrosis from PDB face higher mortality, but survival is still possible with intensive care including blood transfusions.
According to ASPCA data, the majority of dogs receiving prompt veterinary treatment for mothball ingestion survive. The dogs at greatest risk are small breeds, puppies, and dogs with pre-existing liver or kidney conditions (comorbidities that reduce the body's ability to process toxins).
Preventing Mothball Exposure: A Dog Owner's Checklist
- ☐ Eliminate mothballs from your home entirely. This is the single most effective prevention step. Modern alternatives are equally effective and carry zero poisoning risk to pets.
- ☐ Replace with pet-safe alternatives: cedar blocks or chips (naturally repel moths), lavender sachets, airtight garment storage containers, or pheromone-based moth traps that contain no pesticide.
- ☐ Check storage areas your dog can access. Basements, garages, utility closets, and under-stair storage are common mothball locations. Dogs can chew through thin plastic bags and cardboard boxes to reach them.
- ☐ Ask household members and visitors. Grandparents, guests, or house sitters may bring mothball-containing products into your home without realizing the risk.
- ☐ Inspect secondhand items. Vintage clothing, antique furniture, and stored linens purchased from estate sales or thrift stores may carry residual mothball contamination. Air these items outdoors for several days before bringing them inside.
- ☐ Secure trash and disposal. If you're removing existing mothballs from your home, dispose of them in a sealed outdoor trash container — not an indoor bin your dog could raid.
- ☐ Be aware of outdoor hazards. Some people use mothballs in gardens to repel rodents, snakes, or stray animals. This practice is illegal in many jurisdictions (mothballs are EPA-regulated pesticides and must be used only as labeled) and creates a serious risk for dogs on walks.
Related Household Toxins Dog Owners Should Know
If your home contains mothballs, it likely contains other common canine toxins. Cross-reference these hazards and take preventive action:
| Toxin | Where It's Found | Primary Risk |
|---|---|---|
| Rodenticides (rat poison) | Garages, basements, under appliances | Internal bleeding (anticoagulant types), neurological damage (bromethalin), kidney failure (cholecalciferol) |
| Antifreeze (ethylene glycol) | Garages, driveways, puddles | Acute kidney failure — sweet taste attracts dogs; as little as 1–2 teaspoons can kill a small dog |
| Xylitol (birch sugar) | Sugar-free gum, peanut butter, baked goods | Rapid hypoglycemia and acute liver failure; toxic at doses as low as 50 mg/kg |
| Grapes and raisins | Kitchen counters, trail mix, baked goods | Idiopathic acute kidney injury — no known safe dose; tartaric acid identified as likely toxic agent |
| Human NSAIDs (ibuprofen, naproxen) | Medicine cabinets, purses, nightstands | Gastric ulceration, acute kidney failure — never give human pain relievers to dogs |
Frequently Asked Questions About Mothballs and Dogs
Can the smell of mothballs harm my dog?
Inhalation of mothball fumes in a well-ventilated area is unlikely to cause acute poisoning, but prolonged exposure in enclosed spaces (a closed closet or attic where your dog spends time) can cause respiratory irritation, headaches, and chronic low-level toxicity. Dogs with pre-existing respiratory conditions — especially brachycephalic breeds like Bulldogs and Pugs — are more vulnerable. If you can smell mothballs strongly, the concentration of volatile compounds is high enough to be a concern.
My dog licked a mothball but didn't swallow it. Is that dangerous?
Yes, this can still be dangerous. Naphthalene and paradichlorobenzene are absorbed through the mucous membranes of the mouth. Even brief contact can deliver a meaningful dose, particularly in small dogs. Contact poison control or your veterinarian for guidance based on your dog's weight and the duration of contact.
Are cedar mothballs safe for dogs?
Cedar blocks, chips, and rings are a safe, non-toxic alternative to chemical mothballs. Cedar contains natural oils (thujopsene and cedrol) that repel moths without posing a poisoning risk to dogs. Some dogs may be mildly sensitive to the aroma, but cedar does not cause systemic toxicity. Just ensure your dog doesn't chew cedar pieces into small, swallowable fragments that could cause a GI obstruction.
How long does it take for mothball poisoning symptoms to appear in dogs?
Early gastrointestinal symptoms (vomiting, drooling) typically appear within 30 minutes to 2 hours of ingestion. However, more serious systemic effects — hemolytic anemia, liver damage, seizures — may not manifest for 12 to 72 hours. This delayed onset is why waiting to "see if symptoms develop" is dangerous. Seek veterinary care immediately after known or suspected ingestion, even if your dog appears normal.
Can I give my dog hydrogen peroxide to make them vomit after eating a mothball?
Do NOT induce vomiting at home after mothball ingestion unless specifically directed by a veterinarian or poison control specialist. Because mothball compounds are volatile hydrocarbons, vomiting carries a significant risk of aspiration pneumonia — a potentially fatal lung inflammation caused by inhaling vomited material. Your veterinarian can induce vomiting safely in a controlled clinical setting with suction and airway management available if needed.
Anouk Beaumont
All our authors care for dogs every day — read more of their work on the authors page.
