Tansy Dosage: Practical Safety, Uses, and Clear Guidelines

Tansy (Tanacetum vulgare) pops up in old herbal books as a digestive aid, insect repellent, and anti-parasite remedy. Before you try it, know this: tansy contains thujone, a compound that can harm the liver and nervous system in high amounts. That makes dosing and safety the most important parts of using this plant.

Common folk doses—and a big safety flag

Traditional home use usually means a light tea or an external wash. A common folk recipe: 1 teaspoon (about 1–2 g) of dried tansy per 1 cup (240 ml) of hot water, steeped for 5–10 minutes. People historically drank no more than one small cup a day and only for short periods (a few days). That low, short approach is meant to reduce exposure to thujone.

Important: do not use tansy essential oil internally. The oil is concentrated and can cause seizures, severe poisoning, or death even at small amounts. Also avoid large doses of the dried herb or long-term daily use—those increase risk of liver and nervous system harm.

Who should avoid tansy and why

Pregnant or breastfeeding people must avoid tansy. It can stimulate uterine activity and may harm the baby. Don’t give tansy to children, people with epilepsy or seizure history, or anyone with liver disease. If you take blood thinners or other prescription meds, check with your clinician—tansy can interact with drugs or change how your liver handles medicines.

If you feel tingling, confusion, dizziness, severe stomach pain, vomiting, or seizures after using tansy, stop immediately and seek medical help. Those symptoms can signal thujone toxicity.

Want to try tansy safely? Start by asking a healthcare provider or a licensed herbalist. If you get approval, use a single small dose and only short-term. Keep a record of the product (batch, brand), the form (dried herb vs. tincture vs. oil), and the amount you used. If you notice any odd symptoms, stop and call your provider.

For topical use—like an insect-repellent wash—dilute well and test a small skin patch first. If skin becomes red, itchy, or swollen, stop use. For internal use, prefer standardized products from reputable suppliers and avoid homemade concentrated extracts.

Bottom line: tansy has a long folk history, but modern safety concerns around thujone mean you should treat it with caution. If you want a safe herbal alternative for digestion or parasites, ask your clinician for options that have clearer safety data. When in doubt, don’t guess—get professional advice.