Tansy leaves and flowers are toxic if consumed in large quantities. Tansy contains toxic compounds, including thujone, which can cause convulsions and liver and brain damage. It has a long tradition as an effective treatment for intestinal worms, digestive issues, stimulating menstruation, and rheumatism. It remains an effective insect repellent. In Oriental medicine, tansy is known for its ability to Clear Damp and Expel Phlegm. It is used to treat gout, bloating, edema, and sprains.