Mugwort is toxic to cats. While it isn’t always listed on common household plant databases, the Merck Veterinary Manual identifies mugwort ingestion as a recognized toxicosis risk in animals. The primary danger is gastrointestinal irritation, but larger amounts can cause far more serious problems, including seizures and organ damage.
What Mugwort Does to Cats
The most common result of a cat eating mugwort is irritation of the stomach and intestines. You might notice vomiting, diarrhea, drooling, or a loss of appetite. In small amounts, the effects may stay limited to this kind of digestive upset.
With larger ingestions, the picture gets more dangerous. Cats can develop tremors, seizures, coma, and respiratory failure. Mugwort exposure has also been linked to elevated liver enzymes and changes in kidney markers, both signs that the plant’s compounds are stressing those organs. Cats are especially vulnerable because their livers are less efficient at breaking down many plant-based compounds compared to dogs or humans.
Why Cats Are at Higher Risk
Cats lack certain liver enzymes that other animals use to process and clear plant toxins from the body. This means substances that might cause mild irritation in a dog or human can build up and cause organ damage in a cat. Mugwort contains a range of volatile oils and bitter compounds that are responsible for its effects, and a cat’s smaller body size means even a modest amount of plant material represents a proportionally larger dose.
Mugwort is increasingly common in homes and gardens. It’s used in herbal teas, dried herb bundles, moxibustion sticks (used in traditional medicine), and sometimes as a smudging herb. Cats may encounter it as a dried plant, a loose tea, an essential oil, or a growing plant outdoors. Essential oils and concentrated extracts pose a higher risk than a nibble of a fresh leaf because the toxic compounds are far more concentrated.
Signs to Watch For
If your cat has chewed on or eaten mugwort, watch for these signs:
- Mild exposure: vomiting, diarrhea, drooling, reduced appetite
- Moderate exposure: lethargy, wobbliness, repeated vomiting
- Severe exposure: tremors, seizures, difficulty breathing, unresponsiveness
Symptoms from mild ingestion typically appear within a few hours. Neurological signs like tremors or seizures suggest a larger dose and require immediate veterinary attention. If your cat seems disoriented, is having trouble walking, or becomes unresponsive, treat it as an emergency.
What Happens at the Vet
If your cat ate mugwort recently (within one to two hours) and isn’t yet showing symptoms, a vet can induce vomiting to clear the plant material before more of it is absorbed. This option is only safe when the cat is still alert and asymptomatic. Once symptoms like tremors or altered consciousness have started, inducing vomiting becomes unsafe because of aspiration risk.
Activated charcoal is another early intervention. Given by mouth, it binds to toxins in the stomach and intestines and helps prevent them from being absorbed into the bloodstream. It works best when administered soon after ingestion and before significant symptoms develop.
For cats showing more serious signs, treatment is supportive. That typically means IV fluids to protect the kidneys and liver, medications to control seizures if they occur, and monitoring of organ function through blood work. Most cats with mild exposure recover well with prompt care. Severe cases involving seizures or organ damage carry more risk, and recovery depends on how much was ingested and how quickly treatment began.
Keeping Cats Safe Around Mugwort
The simplest approach is keeping mugwort out of your cat’s environment entirely. If you use dried mugwort for tea or herbal purposes, store it in sealed containers. Mugwort essential oil is particularly risky and should never be diffused in a space your cat occupies, since cats can absorb volatile oils through their respiratory tract and skin in addition to ingestion.
If mugwort grows in your garden, consider whether your cat has access to that area. Cats don’t typically seek out bitter plants, but curious nibblers exist, and dried or wilting mugwort can sometimes be more appealing (or less obviously bitter) than fresh growth. Moxibustion sticks and smudge bundles should be stored where cats can’t chew on them, as the compressed dried herb is easy for a cat to bite off in pieces.