From this source:
https://www.botanical.com/botanical/mgmh/f/flecom27.html
"This plant has medicinal properties, and though in England it has never had much reputation as a curative agent it has ranked high in the estimation of herbalists abroad. It was formerly used in dysentery, and on this account received its specific name from Linnaeus, who in his Flora Suecia says that he had been informed by General Keit, of the Russian Army, that his soldiers, in one of their expeditions against Persia, were cured of dysentery by means of this plant. Our old authors call it 'Middle Fleabane' - Ploughman's Spikenard being the Great Fleabane; both names being derived from the fact that,
if burnt, the smoke from them drives away fleas and other insects. The generic name, Pulicaria, refers to this property, the Latin name for the flea being Pulex."