Yes, citronella is toxic to cats. The plant itself, the essential oil, and products containing citronella oil (candles, diffusers, sprays) all pose a risk. Cats lack a key liver enzyme needed to break down the compounds in citronella oil, which means even small exposures can build up and cause harm.
Why Cats Can’t Process Citronella
Most mammals detoxify essential oil compounds through a liver process called glucuronidation. Cats have an unusually low capacity for this process compared to dogs and humans. When a cat absorbs citronella oil, whether through the skin, by breathing it in, or by swallowing it, the compounds linger in the body far longer than they would in other animals. A safety review published in the EFSA Journal specifically flagged this deficit, noting that citronella oil use around cats “needs a wider margin of exposure” precisely because their livers can’t clear it efficiently.
This isn’t unique to citronella. It applies to many essential oils, but citronella is especially common in households during mosquito season, which makes accidental exposure more likely.
Signs of Citronella Poisoning
Symptoms can appear almost immediately or take up to eight hours to develop, depending on how much citronella the cat was exposed to and how it entered the body. Watch for:
- Drooling or pawing at the mouth, especially after licking citronella off their fur
- Vomiting (sometimes with a noticeable citronella smell)
- Difficulty breathing, including wheezing, coughing, rapid breathing, or open-mouth panting
- Uncoordinated walking or difficulty standing
- Lethargy or muscle tremors
- Redness or burns on the lips, gums, tongue, or skin
- Watery eyes and nose
Open-mouth breathing or panting in a cat is always a serious emergency, regardless of the cause. Cats are obligate nose breathers, so switching to mouth breathing signals significant respiratory distress.
How Cats Get Exposed
Direct ingestion of citronella oil is the most dangerous route, but it’s not the most common one. Cats are far more likely to encounter citronella through indirect paths that owners don’t always recognize as risky.
Diffusers
Active diffusers (ultrasonic or nebulizing types) aerosolize essential oils into micro-droplets that float through the room. These tiny droplets can settle on a cat’s fur, and the cat then ingests the oil during normal grooming. According to veterinary toxicologists at Texas A&M, inhaling these oil droplets can also cause a type of pneumonia called foreign body pneumonia. Even passive reed diffusers carry some risk if a cat knocks one over or rubs against it, though the main concern with passive diffusers is respiratory irritation in enclosed spaces.
Candles and Torches
Citronella candles burn the essential oil directly, releasing fumes into the air. Outdoors in a well-ventilated area, the concentration is lower. Indoors, the fumes can build up enough in an enclosed space to cause respiratory irritation, coughing, and watery eyes. If you burn citronella candles on a patio, keep your cat inside and away from the area.
Skin Contact
Essential oils absorb rapidly through skin. If citronella oil spills on a cat, or if a cat walks through a treated area and gets the oil on its paws, it absorbs through the skin and reaches the liver. Concentrated essential oils should never be applied directly to cats for any reason.
The Citronella Plant
The actual citronella grass (Cymbopogon nardus) contains the same essential oils that make the concentrated product dangerous. A cat chewing on the leaves could experience gastrointestinal upset. It’s worth noting that “citronella plants” sold at garden centers are often not true citronella at all. They’re typically scented geraniums (Pelargonium species), which are also toxic to cats, causing GI upset, uncoordinated movement, and muscle weakness.
What Happens at the Vet
If your cat has citronella oil on its fur, bathing the cat with a mild dish soap before heading to the vet helps reduce ongoing skin absorption. Do not try to make the cat vomit. Essential oils can cause aspiration pneumonia if inhaled into the lungs during vomiting, which makes the situation significantly worse.
At the clinic, treatment focuses on supportive care. This typically includes fluids to prevent dehydration, medications to protect the stomach lining if there’s been oral exposure, and antibiotics if there’s concern about secondary infection or chemical burns in the mouth or esophagus. Pain management is provided as needed. In severe oral exposure cases, scarring and narrowing of the esophagus can develop as a complication, though this is uncommon with the level of exposure most household accidents involve.
Most cats recover well with prompt treatment. The critical factor is how much oil was involved and how quickly the cat gets veterinary attention. Mild inhalation exposure in a ventilated space typically resolves faster than direct ingestion of concentrated oil.
Cat-Safe Mosquito Repellent Options
You don’t have to choose between keeping mosquitoes away and keeping your cat safe. Several alternatives work without introducing toxic essential oils into your cat’s environment.
Planting mosquito-repelling species in your yard is the most passive option. Basil, catnip, lemon balm, and rosemary all deter mosquitoes and are safe for cats. Catnip is actually one of the more effective natural mosquito repellents studied, and your cat will likely appreciate it for entirely different reasons.
For personal repellents you wear on your own skin, look for pet-safe formulations at pet supply stores. A homemade option involves boiling the juice of six lemons in a quart of water, steeping it for an hour, and using the cooled mixture as a spray. Cats generally dislike citrus, so they’ll steer clear of it on their own. Just avoid spraying it near their eyes or on any broken skin.
Physical barriers remain the most reliable protection. Window screens, mosquito nets, and fans (mosquitoes are weak fliers and struggle in moving air) keep both you and your cat safe without any chemical exposure at all.