* Eucalyptus leaf has been used as a cure for fever since the early 19th century. Eucalyptus oil as a steam inhalation helps asthma, colds and flu, and whooping cough (J Ethnopharmacol, 2003; 89: 277-83).

* Boneset (Eupatorium, agueweed, hempweed, Indian sage, thoroughwort) is a perennial daisy that works by raising body temperature, which causes perspiration that, in turn, lowers body temperature. The herb’s polysaccharides also activate immune-system T cells to fight bacterial infections.

* Goat’s rue is a wild legume used during the Middle Ages to treat the plague. Like boneset, it induces sweating to break fevers, and can treat parasitic worm infestations and snakebite.

* Marigold (Calendula officinalis) was traditionally used by American physicians to treat conjunctivitis, fever, cuts, scrapes, bruises and burns, as well as minor skin infections.

* Lemongrass (Cymbopogon) also stimulates perspiration to cool the body in summer, and reduce fevers. As a medicinal herb, it is a mild diuretic and stimulant tonic. In southeast Asia and Sri Lanka, it is cultivated as a culinary herb.