Citronella

Is citronella safe for dogs? Mostly in small, sensible doses, and not in the ways people most often use it. A citronella candle burning outdoors, well away from your dog, carries little risk. Spraying concentrated citronella oil on your dog, diffusing it indoors or letting them chew the plant is where problems start, and cats are more sensitive than dogs.

Citronella is also a weaker repellent than its reputation suggests. Below: how each form compares, what the bark collar research found, how cats and horses differ, and what to use instead.

What Citronella Is

Citronella oil is distilled from two tropical grasses, Cymbopogon nardus and Cymbopogon winterianus, close relatives of kitchen lemongrass. Its main aroma compounds, citronellal, citronellol and geraniol, are terpenes, the same broad family of plant aroma molecules found in hemp, lavender and pine.

According to the National Pesticide Information Center fact sheet on oil of citronella, it repels insects by masking the scents that draw them to a target. It does not kill them. It was first registered as a pesticide in the United States in 1948, sits on the EPA’s list of minimum risk pesticides, and turns up in sprays, lotions, candles, pellets and flea collars.

Why It Can Cause Problems for Pets

“Minimum risk” describes people using a product as labeled. It does not mean harmless to a dog who licks it off their coat or a cat who grooms it in. The EPA’s own assessment found little toxicity in lab studies, with skin irritation as the main concern. Pets swallow what’s on their fur, and their noses are far more sensitive than ours.

The Merck Veterinary Manual lists the usual signs of essential oil toxicosis as vomiting, lethargy, drooling, wobbliness and loss of appetite. Breathing in a strong oil can cause watery eyes, nasal discharge, coughing, wheezing and fast breathing.

Candles, Sprays, Oil and the Plant: Form by Form

Citronella candles and torches

This is the lowest-risk way to be around citronella. Burn candles outdoors, upwind and out of reach, and keep your dog from settling right next to the smoke. Skip them indoors, and skip them near any pet with a breathing problem, the same caution the ASPCA gives for diffusers. The bigger practical hazards are the flame, a knocked-over candle and a dog who decides the wax is a snack, which usually means an upset stomach. If a pet drinks or rolls in torch fuel, call for advice.

Human bug sprays and lotions

Don’t put a product labeled for people on your pet. The concentration and the other ingredients aren’t formulated for an animal who licks itself clean. Spray yourself away from your dog and let it dry before a cuddle.

Pure citronella essential oil

Never apply undiluted oil to skin or fur, and don’t run a citronella diffuser in a closed room with your pets. Store the bottle out of reach, as you would tea tree oil or eucalyptus oil.

The plant

Two different plants are sold as “citronella.” Citronella grass is a Cymbopogon grass. The ASPCA lists its close relative, lemongrass (Cymbopogon citratus), as toxic to dogs, cats and horses because of its essential oils and cyanogenic glycosides, with stomach upset in dogs and cats. The potted “mosquito plant” or citronella geranium is a scented Pelargonium, and the ASPCA lists geraniums as toxic to all three species, citing geraniol and linalool, with vomiting, poor appetite, depression and skin irritation. A nibble usually means mild upset. Keep a grazing dog or a curious cat away from the pots.

Citronella Bark Collars: What the Research Shows

A citronella bark collar sprays a puff of scented mist toward the dog’s nose when it detects barking. It is an aversive: it works because the dog dislikes it. The studies are small, and the results are mixed.

• Cornell, 1996. Eight dogs completed trials of both a citronella spray collar and an electric shock collar. Cornell reported the citronella collar reduced or stopped nuisance barking in all eight, and seven of eight owners preferred it.

• Wells, 2001. Thirty Labrador Retrievers wore a citronella collar for three weeks. Barking fell, but the study found dogs generally habituate to the spray. Intermittent wear held its effect longer than daily wear.

• Sargisson and colleagues, 2011. In seven dogs, the collar worked for three. The early drop in barking was not maintained with continued use, and one dog showed serious distress, hiding and trembling continuously.

So, can you spray citronella on your dog to stop barking? Don’t spray it by hand, since you can’t control where it lands and oil near the eyes irritates. A collar can reduce barking in some dogs for a while, but habituation is common and it does nothing about why the dog is barking. The American Veterinary Society of Animal Behavior recommends only reward-based training and lists squirt bottles among the aversive tools to avoid; a spray collar works on the same principle. Boredom, fear, alarm and separation distress each need a different plan.

Dogs, Cats and Horses

Dogs tolerate outdoor candles and pet-labeled products containing citronella reasonably well. The risks are concentrated oil, sprays near the face, and chewing plants or candles.

Cats are the most sensitive. The Merck Veterinary Manual explains that cats are deficient in glucuronyl transferase, a liver enzyme used to process many compounds found in essential oils, and that grooming turns any oil on the coat into an oral dose. Don’t use citronella oils, sprays or diffusers on or around cats, and never use a dog product on a cat. Our page on cat safety covers the wider picture.

Horses are where citronella is most at home. It is a common ingredient in natural fly sprays, and the University of Minnesota Extension describes a six-week study in which a citronella spray reduced tail swishes and shoulder twitches compared with untreated horses. The same guidance notes that homemade recipes can irritate sensitive skin, that EPA-registered products have undergone safety testing, and that repellents need reapplying, especially after a horse walks through wet vegetation. Research on botanical oils against stable flies shows short residual activity, often under 12 hours, so expect to spray more often than with a conventional product. Fly sheets, masks and manure management do more than any spray. The ASPCA lists lemongrass and geraniums as toxic to horses, so keep them out of the pasture.

Signs to Watch For

• Drooling, pawing at the mouth, vomiting or diarrhea after licking or chewing

• Red, itchy skin where a spray or oil was applied

• Squinting, tearing or rubbing the eyes after a spray to the face

• Sneezing, coughing, watery nose or fast breathing near smoke or a diffuser

• Wobbliness, weakness or unusual sleepiness, especially in a cat

What To Do If Your Pet Was Exposed

• Move them to fresh air if the exposure was smoke, a diffuser or a spray cloud.

• Wash oil off the skin and coat with a mild dish soap and plenty of lukewarm water, then rinse well. Merck notes bathing is the main decontamination step for essential oils.

• Don’t make your pet vomit. With essential oils, induced vomiting risks inhaling the oil into the lungs.

• Flush the eyes gently with plain water or saline if they were sprayed.

• Call for advice, especially for a cat, a large amount of oil, torch fuel, or any breathing change: your veterinarian, ASPCA Animal Poison Control at (888) 426-4435 (a consultation fee may apply), or Pet Poison Helpline at (855) 764-7661 ($89 per incident). Have the product label in hand.

Safer Ways to Keep Bugs Off Your Pets

The safest mosquito repellent for a dog is a product registered for that use and labeled for dogs, used at the dose for your dog’s weight. The National Pesticide Information Center is blunt that products labeled for dogs only should never be used on cats. Many dog flea and tick products contain permethrin, which can be deadly to cats. DEET products made for people are not for pets either.

The basics do a lot: empty standing water, avoid dusk walks in peak season, run a patio fan and keep screens repaired. Mosquitoes carry heartworm, and the American Heartworm Society recommends year-round prevention, which no repellent replaces. Our summer pet health guide has more warm-weather basics.

As for which essential oils are safe for dogs to repel bugs: none has good evidence behind it as a stand-alone repellent for pets. In one flea study on dogs and cats, citronella on its own produced no significant reduction in fleas. Neem oil has more data, with its own cautions for cats. Peppermint oil, tea tree and eucalyptus carry real toxicity risks, and a mechanical option like diatomaceous earth belongs on floors, not on pets. If you want a natural product, pick one formulated and labeled for your pet’s species and ask your vet first.

Do Citronella Candles and Plants Actually Work?

Less than the label implies. A 2026 study from New Mexico State University, published in Frontiers in Insect Science, tested seven commercial essential-oil candles against Aedes aegypti mosquitoes. Two standard citronella candles, at 3 and 4.5 percent citronella, did not produce significant repellency. Some candles with higher concentrations of blended oils did better, and the authors concluded that results depend on the formulation.

For pet owners that means two things. A typical citronella candle is mostly ambiance, not protection for you or your dog. And the candles that did work did so by putting out more oil, which is more reason to keep them outdoors, upwind and away from where your pet rests.

As for the potted “mosquito plant,” we found no good evidence that a plant sitting on a patio protects anyone, and the ASPCA lists geraniums as toxic to pets.

Pet-safe plants for a shared patio

If you want scented plants where your pets hang out, these are listed as non-toxic by the ASPCA. Treat them as safe greenery, not as a repellent.

• Lemon balm — non-toxic to dogs, cats and horses.

• Rosemary — non-toxic to dogs, cats and horses. See our rosemary entry.

• Basil — non-toxic to dogs and cats. See our basil entry.

Catnip is often suggested too, but the ASPCA lists catnip as toxic to cats: it can cause vomiting and diarrhea. A pot on the patio is fine for most cats; just don’t expect it to keep mosquitoes away.

When to Call Your Veterinarian

Call if your pet ate a candle, a plant or a product, if vomiting or diarrhea continues, if skin irritation spreads or blisters, or if you see any breathing change or wobbliness. Call right away for any cat exposed to citronella oil, and ask your vet before choosing a flea, tick or mosquito product for a puppy, kitten, senior or pregnant pet.

How It Fits With Hemp

Hemp is not a bug repellent, and nothing about CBD keeps mosquitoes or fleas away. Where the two meet is barking. If your dog barks from worry or overstimulation, the lasting fix is training plus a calmer routine: exercise, enrichment and predictable days. Some owners add hemp as part of that routine to support calm. Our hemp for dogs collection explains the options and serving sizes; give it with a meal.

Frequently Asked Questions

Is citronella safe for dogs?

Outdoor candles used at a distance and pet-labeled products used as directed are generally fine. Concentrated oil on the skin, indoor diffusing and chewing the plant are the risky uses.

What is the safest mosquito repellent for dogs?

A product registered and labeled for dogs, dosed by weight, chosen with your vet. Pair it with removing standing water and year-round heartworm prevention. Never use human DEET sprays on pets.

Can I spray citronella on my dog to stop barking?

Don’t spray it by hand. Collars reduced barking in some small studies, but dogs often habituate, some show distress, and it doesn’t address the reason for the barking. Reward-based training is the approach veterinary behaviorists recommend.

What are safer alternatives to citronella for dogs?

Vet-recommended products labeled for dogs, plus fans, screens, avoiding dusk walks and emptying standing water.

What essential oils are safe for dogs to repel bugs?

None has strong evidence as a stand-alone pet repellent, and several, including tea tree, are common causes of poisoning. Use species-labeled products instead of homemade oil blends.

Is citronella safe for cats?

Not as an oil, spray or diffuser. Cats process essential oils poorly and groom them off their coat. An outdoor candle far from where your cat spends time is the only reasonable use.

Is citronella fly spray safe for horses?

Citronella is widely used in horse fly sprays, and one six-week study found fewer tail swishes and twitches in treated horses. Choose an EPA-registered product, patch-test on sensitive skin and expect to reapply often.

Do citronella candles keep mosquitoes away?

Not reliably. In a 2026 lab study, two standard citronella candles produced no significant repellency against mosquitoes. Pet-labeled products, screens, fans and removing standing water do more.

Do dogs hate the smell of citronella?

Many do. Dogs’ noses are far more sensitive than ours, which is why a citronella bark collar works as an aversive at all. That is also a reason not to spray it near their face or diffuse it in a closed room.

What plants repel mosquitoes and are safe for pets?

No potted plant has good evidence as a repellent. If you want safe scented plants on the patio, the ASPCA lists lemon balm, rosemary and basil as non-toxic to dogs and cats. Citronella geraniums are listed as toxic.