Feverfew (Tanacetum parthenium) was an important mediaeval herb. It is a bushy perennial with feathery, bright green leaves and small, daisy-like white flowers with yellow centres, similar to chamomile but its flowers are flat-topped. Its name, feverfew, or ‘fever reducer’ derives from the Latin febrifugia, meaning ‘to put fever to flight’. It was used, as…