Mugwort (Artemisia vulgaris) also known as Folium Artemisiae Argyi (Aiye), felon herb, St. John's herb, chrysanthemum weed, sailor's tobacco, and moxa is a perennial member of the Compositae family, and a close relative of wormwood (Artemisia absinthium L.). Mugwort's generic name is from that of the Greek moon goddess Artemis, a patron of women. Mugwort has long been considered an herbal ally for women with particular benefit in regulating the menstrual cycle and easing the transition to menopause. The common name may be from the old English word moughte meaning "moth," or mucgwyrt, meaning "midgewort," referring to the plant's folk use to repel moths and other insects.

Mugwort has a long history of folk tradition and use. Anglo-Saxon tribes believed that the aromatic mugwort was one of the nine sacred herbs given to the world by the god Woden. It was used as a flavoring additive to beer before hops (Humulus lupulus) became widely used. Mugwort is considered a magical herb, with special properties to protect road-weary travelers against exhaustion. The Romans planted mugwort by roadsides where it would be available to passersby to put in their shoes to relieve aching feet. St. John the Baptist was said to have worn a girdle of mugwort when he set out into the wilderness. Some of the magic in mugwort is in its reputed ability to induce prophetic and vivid dreams when the herb is placed near the bed or under the sleeper's pillow. In Pagan ceremony, a garland or belt of mugwort is worn while dancing around the fire during summer solstice celebrations. The herb is then thrown into the fire to ensure continued protection throughout the coming year.

Mugwort is a tall and hardy European native with stout, angular, slightly hairy stems tinged with a purple hue. Leaves, which may be as long as 4 in (10 cm), are deeply divided with numerous lance-shaped, pointed segments, which may be toothed or entire. They are arranged alternately along the erect, grooved stem and are a dark green on top and pale green with downy hairs on the underside. Mugwort has a pungent aroma when the leaves are crushed. In late summer the small reddish-yellow disk flowers cluster in long spikes at the top of the plant. Mugwort may reach to 6 ft (2 m) or more in height. This tenacious herb has naturalized throughout North America and may be found growing wild in rocky soils, along streams and embankments, and in rubble and other waste places, particularly in the eastern United States. In some areas, including North Carolina and Virginia, mugwort is characterized as a noxious, alien weed. Mugwort root is about 8 in (20 cm) long with many thin rootlets. It spreads from stout and persistent rhizomes.