Mugwort is considered mildly toxic to dogs. While a small nibble of the plant is unlikely to cause a serious emergency, mugwort contains compounds that can irritate your dog’s digestive system and, in larger amounts, affect the nervous system. The risk increases significantly with concentrated forms like essential oils or dried mugwort supplements.
What Makes Mugwort Harmful
Mugwort (Artemisia vulgaris) belongs to the same plant family as wormwood and sagebrush. The whole group produces a compound called thujone, which acts as a natural insect repellent for the plant but is toxic to mammals in sufficient quantities. Thujone overstimulates the nervous system, and dogs are more sensitive to it than humans because of their smaller body size and different liver metabolism.
The plant also contains volatile oils and bitter compounds that irritate the lining of the stomach and intestines. These are the same properties that made mugwort popular in traditional medicine as a digestive stimulant, but what nudges a human stomach can overwhelm a dog’s.
Symptoms to Watch For
If your dog eats mugwort, the most common reaction is gastrointestinal upset. This typically looks like:
- Vomiting, often within the first few hours
- Diarrhea, which may be watery or contain mucus
- Drooling or lip-licking more than usual
- Loss of appetite lasting a day or two
With larger amounts, the thujone content can cause neurological symptoms. These are less common but more serious: tremors, disorientation, wobbliness when walking, or in rare cases, seizures. Small dogs and puppies are at the highest risk for these effects because even a modest amount of plant material delivers a proportionally larger dose relative to their body weight.
Mugwort is also a common allergen. Dogs that roll in or chew on the plant may develop skin irritation, redness, or itching around the mouth and face. Dogs with existing environmental allergies may be more reactive.
Fresh Plant vs. Essential Oil
There’s a big difference between your dog chewing on mugwort growing in the yard and getting into a bottle of mugwort essential oil. The fresh plant is mildly toxic, meaning a few bites will likely cause stomach upset and nothing more. Essential oils are highly concentrated, sometimes containing hundreds of times the thujone level found in the raw plant. Even a small amount of mugwort essential oil ingested or absorbed through the skin can cause serious toxicity in dogs, including liver damage and seizures.
Dried mugwort sold as an herbal supplement or for smudging falls somewhere in between. It’s more concentrated than the fresh plant, so less material is needed to cause a problem. If your dog gets into a bag of dried mugwort, treat it with more urgency than a garden nibble.
What to Do If Your Dog Eats Mugwort
For a small amount of fresh mugwort, monitor your dog closely for the next 12 to 24 hours. Mild vomiting or soft stool that resolves on its own is typical and not usually dangerous. Make sure your dog has access to fresh water, since vomiting and diarrhea can lead to dehydration.
Contact your vet or an animal poison control hotline if your dog ate a large quantity of the plant, got into dried mugwort or supplements, or ingested any amount of mugwort essential oil. Also call if you notice tremors, confusion, excessive lethargy, or repeated vomiting that doesn’t stop after a few hours. Having an estimate of how much your dog consumed and your dog’s weight will help the vet assess the situation quickly.
Keeping Dogs Away From Mugwort
Mugwort is a fast-spreading perennial that thrives in disturbed soil, roadsides, and garden edges across most of North America and Europe. It grows tall with deeply lobed leaves that are dark green on top and silvery underneath, with a distinctive sage-like smell when crushed. If it’s growing in your yard and your dog tends to graze on plants, pulling it before it establishes deep roots is the most practical solution. Mugwort spreads aggressively through underground runners, so removing it early saves effort later.
Store any mugwort products, including teas, dried bundles, and especially essential oils, well out of your dog’s reach. Dogs are often attracted to novel smells, and mugwort’s strong herbal scent can draw a curious nose straight to it.