The common name "lady's slipper" refers to the distinctive shape of these beautiful orchids, members of the genus Cypripedium that are native to North America and Europe, as well as the Paphiopedilum species native to Southeast Asia. Other "slipper" orchid species are native to South America. Typically, the yellow lady's slipper Cypripedium calceolus var. pubescens (now called Cypripedium parviflorum var. pubescens) is used medicinally in Europe and North America. Cypripedium montanum, the rare mountain lady's slipper native to North America, is also wildcrafted (collected in the wild).

Many of the Cypripedium lady's slipper species are endangered and have proven very difficult to cultivate; even just collecting the flower alone may be enough to kill the plant, and transplantation from the wild is rarely successful. Alternatively, some herbalists recommend using the roots of another species called stream orchid or helleborine ( Epipactis helleborine), which has the same purported effects, is more widespread, and is relatively easy to cultivate.1

Traditionally, lady's slipper root was classified as a "nervine," indicating its purported healing and calming effect on the nerves. This term, however, is no longer used in medicine today.

Despite a complete absence of scientific evidence that it is effective, lady's slipper is sometimes used today either alone or as a component of formulas intended to produce treat anxiety or insomnia.

Lady's slipper is also sometimes used topically as a poultice or plaster for relief of muscular pain,2 but again there is no evidence that it is effective.