An enema (plural enemata or enemas) is the procedure of introducing liquids into the rectum and colon via the anus. Enemas can be carried out for medical reasons (as a treatment for constipation), as part of alternative therapies, and also for erotic purposes, particularly as part of BDSM activities. In earlier times, they were often known as clysters. Enemas have even been used to administer beverage alcohol to alcoholics who have developed stomach ulcers.