The leaves and flowers are toxic if consumed in large quantities; the volatile oil contains toxic compounds including thujone, which can cause convulsions and liver and brain damage. Some insects, notably the tansy beetle Chrysolina graminis, have evolved resistance to the toxins and subsist almost exclusively on the plant. Yellow flower heads are produced in terminal clusters from mid-to-late summer. The scent is similar to that of camphor with hints of rosemary. Tansy was used to treat intestinal worms, rheumatism, digestive problems, fevers, sores, and to “bring out” measles.Tansy has also been cultivated and used for its insect repellent and in the worm warding type of embalming. It was packed into coffins, wrapped in funeral winding sheets, and tansy wreaths were sometimes placed on the dead.