Mineral oil, or liquid petrolatum, 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, which is prepared from a plant seed, helps elimination by encouraging the peristaltic movements.
Castor oil is a strong cathartic that effects complete evacuation of the bowels.
Its administration is followed by temporary constipation. Laxatives should be employed only with the advice of a physician. 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. In this way laxatives can be the cause of chronic constipation rather than its cure.