Shepherd's purse is a Eurasian plant which grows widely all over the world. In many regions, it is treated as a weed and can in fact sometimes be invasive, but shepherd's purse also has a long history of use in herbal medicine. Preparations of this plant intended for pharmacological use can be found in health food stores and through practitioners of herbal medicine, and some people also prepare their own with wildcrafted shepherd's purse.
Known formally as Capsella bursa-pastoris, this plant has a number of colorful alternate names including lady's purse, pepper and salt, blindweed, shepherd's bag, Bourse de pasteur, rattle pouches, witches' pouches, Hirtentasche, and shepherd's scrip. Many of these names reference to the distinctive appearance of the seed pods, which do indeed resemble the purses once carried by people of all genders in medieval Europe.
This plant is a cool season annual which can produce several generations in a year if the conditions are favorable. Shepherd's purse starts as a rosette of dark green, hairy leaves which eventually produce a stalk. The plant develops creamy flowers which mature into heart-shaped dangling seed pods. As the pods dry out, they tend to rattle due to the trapped seeds inside, and when cracked open, they reveal several compartments which hold seeds.
Shepherd's purse is a member of the mustard family, and resembles some members of this plant family. Like other brassicas, it can thrive in a variety of climates, and it is very durable. It can sometimes be found growing by the side of the road in addition to being found in meadows and other natural areas.
Historically, shepherd's purse was used in the treatment of a number of conditions, with all parts of the plant being usable. Most notably, it was taken internally to treat bleeding, including uterine bleeding and intestinal bleeding. In the case of uterine bleeding, shepherd's purse appears to have a dual effect, because it acts as an astringent to stop bleeding and it promotes the contracture of the uterine muscles, helping the uterus expel blood and firm up. Shepherd's purse tea has also been prescribed for the treatment of diarrhea, and the herb can be applied topically for treatment of various skin conditions.
The pharmacological effects of this plant are not well understood. Studies do seem to suggest that it contains active ingredients which can indeed do things like stopping bleeds, but the plant is not widely used in modern medical treatment.