Psilocybin mushrooms possess psychedelic properties. They are commonly known as "magic mushrooms" "mush" or "shrooms" and are available in smart shops in many parts of the world, though some countries have outlawed their sale. A number of other mushrooms are eaten for their psychoactive effects, such as fly agaric, which is used for shamanic purposes by tribes in northeast Siberia, Russia. They have also been used in the West to potentiate, or increase, religious experiences. Because of their psychoactive properties, some mushrooms have played a role in native medicine, where they have been used in an attempt to effect mental and physical healing, and to facilitate visionary states. One such ritual is the Velada ceremony. A practitioner of traditional mushroom use is the shaman and curandera (priest-healer) María Sabina.