The magico-theurgical tradition of Kabbalah, using the inner workings of creation, as well as the names of G-d and their permutations, to perform things that defy the laws of nature. Famous examples include R' Yochanan and Resh Lakish creating cows, and Rava, R' Eliyahu Baal Shem, and the Maharal creating golems. Other common applications are "kameas" (amulets) and healing the sick. It is the application of "Kabbalah Iyunis" (Contemplative Kabbalah).
Recorded practitioners of Practical Kabbalah have been few and far in between throughout Jewish history. It's practitioners are always among the holiest of Jews, and its use is always for the sake of Heaven. Nevertheless, many Kabbalists have forbidden its practice entirely.
Not to be confused with sorcery-kishuf-magic, in which many of the same things can be effected, but with the use of impure forces.