In medicine, a cathartic is a substance that accelerates "defecation. This is in contrast to a "laxative, which is a substance which eases defecation, usually by softening "feces. It is possible for a substance to be both a laxative and a cathartic. However, agents such as "psyllium seed husks increase the bulk of the feces.
Cathartics such as "sorbitol, "magnesium citrate, "magnesium sulfate, or "sodium sulfate were previously used as a form of "gastrointestinal decontamination following "poisoning via ingestion. They are no longer routinely recommended for poisonings. High-dose cathartics may be an effective means of ridding the lower gastrointestinal tract of toxins; however, they carry a risk of electrolyte imbalances and dehydration.
During the "1918 flu pandemic, cathartics were used in the "Fort Lewis, WA, area. An original report by Elizabeth J. Davies, a "public health nurse, mentions cathartics, "pneumonia jackets and copious amount of drinks as treatments for influenza patients.["citation needed]