Is Wormwood Poisonous? – Toxicity to Humans, Dogs, and Cats
Yes. Wormwood (Artemisia absinthium) is poisonous to humans, dogs, cats, and horses. All parts of the plant contain thujone, a neurotoxic compound. Severity depends on the quantity ingested and the form. A few bites of raw leaf may cause stomach upset. Concentrated essential oil is a genuine medical emergency.
What Makes Wormwood Toxic?
Thujone is the primary driver of wormwood’s toxicity. It works by disrupting GABA receptors in the nervous system, which can trigger seizures and other neurological symptoms at high enough doses.
Wormwood also contains artemisinin (present in some Artemisia species) and sesquiterpene lactones, which contribute to its toxicity profile.
Form matters enormously. The raw plant is dangerous in sufficient quantity. Wormwood essential oil is far more concentrated and significantly more dangerous. Even small amounts can cause severe poisoning in both humans and animals.
Which Parts of Wormwood Are Toxic?
All parts. Leaves, stems, flowers, roots, and seeds all contain volatile oils including thujone. There is no safe part of the plant.
Symptoms of Wormwood Poisoning
Humans
- Vomiting and diarrhea
- Stomach pain and nausea
- Seizures and tremors
- Delirium and hallucinations (historically associated with absinthe)
- Kidney damage at high doses
Dogs and Cats
- Vomiting and diarrhea
- Lethargy and depression
- Tremors and muscle fasciculations
- Seizures
- Temporary blindness
- Kidney damage
Horses
- Gastroenteritis
- Neurological symptoms similar to dogs and cats
Children
Children face greater risk at lower doses because of their smaller body weight. A quantity that would cause mild stomach upset in an adult can be significantly more serious in a child.
What to Do If Wormwood Is Ingested
Do not induce vomiting unless a veterinarian or poison control specialist specifically instructs you to do so.
- Call poison control at 1-800-222-1222 (US) or your local equivalent.
- Contact your veterinarian if a pet is involved.
- Bring a photo or sample of the plant if possible. Accurate identification speeds up treatment.
- Monitor for 24 to 48 hours for neurological symptoms including tremors, disorientation, or seizures.
- Note the time of ingestion and approximate quantity if known.
Time matters. The sooner you call, the sooner you get professional guidance.
Wormwood in the Garden - Safe Handling
Wormwood is sometimes grown as an ornamental for its silver-gray foliage and drought tolerance. It can be handled safely with a few basic precautions.
- Wear gloves when pruning or handling any part of the plant.
- Position wormwood where children and pets cannot reach it.
- After handling, wash your hands before touching your face or eyes.
- If you suspect your pet has chewed on wormwood, monitor closely for symptoms and call your vet.
On the upside: wormwood is naturally deer- and rabbit-resistant. That persistence in the garden is partly why it has spread so widely. It survives browsing pressure that wipes out less defended plants.
Look-Alike Plants - Is It Really Wormwood?
Wormwood (A. absinthium) is often confused with two common look-alikes that have very different toxicity profiles.
Common mugwort (A. vulgaris) has much lower thujone content and is not considered highly toxic. It is a widespread roadside plant and garden weed.
Tarragon (A. dracunculus) is a widely used culinary herb with negligible toxicity. You are almost certainly not looking at tarragon if the plant is growing wild without cultivation.
To distinguish wormwood from mugwort: wormwood has finely divided silver-gray leaves with a strong aromatic scent. Mugwort leaves are greener, less divided, and less aromatic. If you are unsure, treat it as potentially toxic.
Frequently Asked Questions
Is absinthe dangerous?
Modern commercially sold absinthe contains very low thujone levels due to distillation processes and regulatory limits (in the US, allowable thujone is below 10 ppm). Historical absinthe was more concentrated and more dangerous. Today the primary risk from absinthe is its high alcohol content, not the wormwood. That said, anyone with seizure disorders or neurological conditions should avoid it.
Can wormwood kill a dog or cat?
In severe cases, yes. Large quantities of raw plant or any amount of essential oil can cause seizures, organ failure, and death. However, a small mouthful of leaf from the garden is more likely to cause vomiting and lethargy than a life-threatening crisis. Either way, contact your vet immediately.
Is it safe to grow wormwood in a garden with pets?
It can be grown safely with precautions: gloves when handling, restricted access so pets and children cannot reach it, and prompt cleanup of any fallen plant material. Many gardeners grow it without incident. The risk increases if you have pets that chew on plants.
What does wormwood look like?
Wormwood is a bushy perennial growing 3 to 4 feet tall. Its defining feature is silver-gray, finely divided leaves with a strong, somewhat bitter aroma. Small yellow flower heads appear in summer. The plant is native to Europe and parts of Asia and has naturalized widely.
Is wormwood safe during pregnancy?
No. Wormwood is contraindicated during pregnancy and should not be ingested in any form. The thujone content can cause fetal harm. If you are pregnant and have been exposed to wormwood, consult your healthcare provider.
Is wormwood essential oil ever safe for pets?
No. Wormwood essential oil is never safe for pets. Essential oils are far more concentrated than the raw plant and are rapidly absorbed through the skin and mucous membranes. Diffusing wormwood oil in a home with cats or dogs is also not recommended.
Are there safe alternatives for pet deworming?
Yes. Several vet-approved deworming medications are available by prescription or over the counter. Products containing pyrantel, praziquantel, or fenbendazole are standard options. For garden pest control, diatomaceous earth (food-grade), beneficial nematodes, and other non-toxic methods are effective. Do not use wormwood for any form of pet deworming. The risks far outweigh any purported benefits.