An enema (plural enemata or enemas) is the proceure 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 a remedy for encopresis, as part of alternative health therapies, and also for erotic purposes, particularly as part of BDSM activities. In earlier times, they were often known as clysters, and were probably used more frequently than at present.