Tansy (
Tanacetum vulgare) is a perennial herb of the aster family with bright yellow flowers, formerly used as a flavouring for puddings and omelettes. Said to have been eaten at Easter in memory of the 'bitter herbs' of the Jewish Passover festival.
John Gerard's Herbal of 1597 speaks of it as "pleasant in taste", and recommends tansy sweetmeats as "an especial thing against the gout". Tansy is highly toxic to insects, and slightly toxic to humans.