a medicine that loosens the bowel contents and encourages evacuation. One with a mild or gentle effect is also known as an
aperient; one with a strong effect is referred to as a
cathartic or
purgative. Bland laxatives may be used temporarily in treatment of
constipation along with other measures.
mineral oil and olive oil act as lubricants; sometimes mineral oil is used in combination with
agar, which is bulk-producing.
cascara sagrada aromatic fluid extract and
milk of magnesia are two other mild laxatives.
Psyllium hydrophilic mucilloid, a preparation from a plant seed, helps elimination by encouraging peristaltic movements. Saline purges, such as
sodium phosphate and
magnesium sulfate (Epsom salt), flush the intestinal tract by preventing the intestines from absorbing water; evacuation takes place as soon as water accumulates.
castor oil is a strong cathartic that causes complete evacuation of the bowels. Its administration is followed by temporary constipation.
Dangers of Laxatives. Laxatives should be used only with the advice of a health care provider. Constipation may be a symptom of serious organic illness as well as the result of improper diet and habits. Also, laxatives taken regularly tend to deprive the colon of its natural muscle tone and thus can be the cause of chronic constipation rather than its cure. Mineral oil taken regularly interferes with the absorption of certain vitamins, especially those that are fat soluble. It can also seep into the lungs, causing a reaction resembling
pneumonia, especially in older people. Purgative salts can produce
dehydration. Laxatives that produce bulk may cause stonelike balls (
bezoars) to develop. A strong cathartic such as castor oil can have fatal results if used when there is nausea, vomiting, abdominal pain, or other symptoms of
appendicitis. It is also dangerous to use during pregnancy. Children cannot use as large dosages or as strong laxatives as adults.