Feverfew (Tanacetum parthenium) is a traditional medicinal herb which is commonly used to prevent migraine headaches, and is also occasionally grown for ornament. The plant grows into a small bush up to around 46 cm (18 in) high with citrus-scented leaves, and is covered by flowers reminiscent of daisies. It spreads rapidly, and they will cover a wide area after a few years. It is also commonly seen in the literature by its synonyms, Chrysanthemum parthenium and Pyrethrum parthenium. It is also sometimes referred to as bachelor's buttons or featherfew.