In the Middle Ages, mugwort was used as a magical protective herb. Mugwort was used to repel insects, especially moths, from gardens. Mugwort has also been used from ancient times as a remedy against fatigue and to protect travelers against evil spirits and wild animals. Roman soldiers put mugwort in their sandals to protect their feet against fatigue.

Much used in witchcraft, mugwort is said to be useful in inducing lucid dreaming and astral travel. Consumption of the plant, or a tincture thereof, prior to sleeping is said to increase the intensity of dreams, the level of control, and to aid in the recall of dreams upon waking. One common method of ingestion is to smoke the plant. Colloquially, this practice is known as "Having a tasp before having a nap."