What Do Mothballs Do to Dogs And Pets in General?

Mothballs are deceptively toxic pesticides that can poison dogs. Learn why they're dangerous, signs of exposure, what to do if your dog eats them, and safer alternatives to repel moths without endangering pets.

February 8, 2024
min read
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Mothballs may conjure up innocent memories of childhood summers and sweet seasonal clothing. Yet those deceptively tiny balls harbor a dark secret - they can be profoundly toxic and even lethal if our curious canine companions happen to pop them in their mouths or get trapped in closed spaces filled with their noxious fumes.

Within their tissue paper shells, mothballs slowly emit a heavy vapor laced with potent pesticides. Both the chemicals themselves and their concentrated doses make mothballs poisonous land mines when left where unsuspecting dogs can access them. Even a few mothballs can overwhelm a dog's metabolism and lead to severe neurological, blood, liver and kidney damage. Quick, aggressive treatment offers the only hope to avoid catastrophic and lasting repercussions.

We may take these commonplace pest control products for granted. But make no mistake - mothballs present an insidious and very real danger to the delicate constitutions of our furry best friends. Read on to uncover more about how seemingly harmless mothballs can harm helpless dogs, critical action steps if exposure happens, and what to watch for in the hours and days following ingestion or suspicious contact with those deathly floating orbs. Forewarned is forearmed when it comes to protecting beloved pets.

What are mothballs and how are they used?

Mothballs are small balls of chemical pesticide that are used to repel and kill cloth-eating moths and their larvae. The active ingredients in traditional mothballs are either naphthalene or paradichlorobenzene. Naphthalene mothballs emit a strong, pungent odor and paradichlorobenzene mothballs emit a more subtle medicinal smell.

Mothballs work by turning from a solid state to a gas vapor that is slowly released over time. As the vapors spread, they create a toxic environment that moths find repellant. The mothballs kill moth larvae that come into contact with the chemicals. The vapors are dense and heavy, so they sink down into fabrics instead of dissipating into the air.

People commonly use mothballs to protect out-of-season clothing, carpets, furniture, and other household textiles from moth infestations. They simply place mothballs or mothball-filled sachets in boxes and closets that contain susceptible items. The mothballs then work to fumigate the enclosed spaces and materials. A few mothballs can protect a surprisingly large area from moths.

Why are mothballs toxic to dogs?

Mothballs are highly toxic to dogs primarily because of the pesticides they contain. Dogs are extremely sensitive to pesticides and mothballs have very concentrated doses.

The naphthalene and paradichlorobenzene work as neurotoxins in dogs. When dogs ingest or breathe in the chemicals, the pesticides disrupt neurological impulses and damage neurons, red blood cells, liver cells, and kidneys. Even small exposures can cause severe poisoning.

Additionally, as the mothball vapors build up in enclosed spaces, they create a toxic environment for dogs. Dogs trapped in rooms or vehicles with mothballs are vulnerable to pesticide poisoning simply from breathing the concentrated gas fumes.

The toxicity comes from both the ingredients themselves and the high doses used. Mothballs have to emit enough pesticide to permeate fabrics and kill moth larvae, making them very potent chemical products. Dogs cannot metabolize or excrete the toxin well, allowing it to accumulate to dangerous levels within their bodies. This makes mothballs a serious poisoning risk.

What makes mothballs poisonous for dogs?

The ingredients naphthalene and paradichlorobenzene make mothballs extremely toxic for dogs. Here’s a closer look at how each chemical causes poisoning:


  • Damages red blood cells, causing anemia or hemolytic anemia
  • Causes nausea and vomiting
  • Stops neurons from firing properly, leading to neurological symptoms
  • Stops liver and kidney cells from working correctly
  • Leads to liver or kidney failure when exposure is high


  • Accumulates in body fat stores over time after lower exposures
  • Released back into the blood as fumes build up with higher exposures
  • Breaks down red blood cells
  • Stops nutrients, water and waste from moving properly in kidneys
  • Causes fluid buildup and swelling in lungs
  • Disturbs normal functioning of neurons

In high enough doses, both mothball chemicals can cause seizures, tremors, weakness, difficulty breathing, collapse, coma and death in dogs. The poisoning damages multiple organ systems in the body.

Even after mild to moderate poisoning, dogs may experience long-lasting health issues. Their livers, kidneys and blood cell counts may never fully recover.

dog playing with paper

How many mothballs could be toxic to a dog?

It does not take much for mothballs to potentially poison dogs due to the concentrated pesticides they contain. Here are some general guidelines on dangerous mothball exposure:

For small dogs under 22 lbs:

  • Just 1-2 mothballs could cause poisoning
  • breaths in fumes from 2-8 mothballs may be toxic

Medium dogs 22 - 55 lbs:

  • 2-3 mothballs may cause poisoning if ingested
  • fumes from 8-12 mothballs could cause toxicity

Large 55+ lb dogs:

  • 4-5 mothballs might be poisonous if eaten
  • mothball vapor from half a box (25 balls) upward could intoxicate

Puppies and small dogs are at greatest risk since they weigh less, but even one or two mothballs may pose a hazard to dogs of any size. Dogs trapped in enclosed spaces with mothballs are most vulnerable to toxic effects - the fumes can quickly build up to dangerous levels.

Any mothball ingestion or concerning exposure should be treated as an emergency by immediately contacting your veterinarian or the ASPCA Animal Poison Control Center. Quick action greatly improves the chances of recovery and survival.

What should I do if my dog eats mothballs?

If your dog ingests mothballs, you need to take emergency action right away. Follow these important steps:

  1. Identify number and type. Try to identify how many mothballs were eaten, what ingredients they contain, and when it happened.
  2. Call animal poison control. Contact your vet or the 24/7 ASPCA Animal Poison Control Center at 888-426-4435 for life-saving advice.timing is critical for effective treatment.
  3. Protect yourself first. Avoid direct contact with your dog’s saliva, vomit or diarrhea which could contain toxic pesticide residues. Wear gloves and wash hands thoroughly afterwards.
  4. Induce vomiting if advised. The poison experts may instruct you to give hydrogen peroxide to make your dog vomit up the mothballs before they are digested and absorbed. Do not make your dog vomit unless told to do so by the vet.
  5. Rush to emergency vet. Get your dog to the nearest emergency veterinary hospital immediately. They can provide supportive care, decontamination treatment, anticonvulsant medication, IV fluids, blood transfusions and other important, timely care.
  6. Provide info to the vet. Give the vet details on exposure, symptoms, treatments given and advise from the poison control experts. This info guides diagnosis and tailored emergency treatment.
  7. Monitor health afterward. Your dog may need extended care such as kidney dialysis, liver support and blood cell boosters depending on the severity of poisoning. Watch for delayed or prolonged symptoms.

Fast response makes all the difference in preventing severe, lasting harm when dogs eat mothballs. Always contact poison control right away rather than waiting to see if symptoms appear. Many exposures require aggressive decontamination and support.

What are the signs of mothball poisoning?

Dogs poisoned by mothballs may show these symptoms:

Mild to Moderate Poisoning Signs:

  • Excess salivation
  • Nausea and vomiting
  • Diarrhea
  • Tremors
  • Lethargy
  • Confusion
  • Increased thirst and urination
  • Abnormal pupil size

Severe Poisoning Signs

  • Seizures
  • High fever
  • Rapid heart rate
  • Difficulty breathing
  • Collapse
  • Coma or death

Symptoms typically start 30 minutes to 4 hours after ingestion. However signs can appear rapidly after high exposures or be delayed up to 2 to 3 days afterward.

Dogs may not show obvious outward symptoms in milder cases. Instead, they experience internal organ and cell damage that leads to secondary issues like anemia, fluid buildup in lungs, liver failure and kidney dysfunction over the next few days. These life-threatening crises can suddenly arise well after the initial exposure.

That’s why suspected mothball poisoning requires veterinary oversight for at least 24 hours. Blood tests help monitor for organ injury and other blood abnormalities during this critical window when patients first appear recovered but are still at risk.

How to avoid mothball poisoning scenarios

With simple awareness and preventative steps, we can help dogs steer clear of the serious perils of mothball poisoning. Here are some top tips:

Lock Away Mothballs

Keep mothballs and mothball-containing products in securely latched plastic bins up on high shelves. Never store mothballs in bags that dogs can rip into. Make sure rooms are well-ventilated wherever you use mothballs.

Take Special Care in Vehicles

Dogs left waiting in vehicles are at high risk for poisoning from fumes if mothballs are present in the back or trunk area. Well-meaning owners may toss in mothballs to fend off bugs, unaware this turns parked cars into gas chambers. Always check carefully for mothball fumes or spills before allowing dogs into rear cargo areas.

Try Cedar Wood as an Alternative

Cedar wood naturally repels moths with its strong scent, while being non-toxic for dogs. You can buy cedar-filled storage containers, sachets and closet liner boards. These contain helpful Eastern red cedar oil. Its rustic aroma also imparts a pleasant seasonal ambiance. Just avoid cedar mulch, which lacks the repellent qualities.

Inspect Yards & Play Areas

Make sure your own yard is clear of windblown mothballs from neighboring homes. Also check public parks and playgrounds before letting dogs off leash, since mothballs sometimes get scattered in outdoor public spaces illegally. Their size, shape and halo of fumes makes them tough for dogs to avoid.

Discard Old Mothballs Safely

Responsibly seal up old solid mothballs in extra plastic bags and discard in outside garbage bins, not via street garbage pick-up. This prevents chemicals from leaching into landfill groundwater. Old mothballs may appear benign but still emit dangerous pesticide vapors.

By proactively mothball-proofing homes, vehicles and yards, owners can set up reliable barriers between dogs and these extremely hazardous pesticides. It only takes an unguarded moment for irreversible tragedy to unfold. Using safer cedar-based deterrents also offers reliable protection minus the toxicity risks for pets.

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Our mission is to empower you with the knowledge to curate a wardrobe that not only reflects your personal style but also aligns with environmentally friendly practices. From exploring the wonders of natural mothballs and sustainable garment storage to diving deep into DIY solutions and green living, we're here to guide you on a journey towards a more eco-conscious, stylish, and intentional lifestyle.

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