purgative

A purgative is a substance or preparation that induces purgation, meaning rapid evacuation of the bowels. In medical use, purgatives are often considered a subset of laxatives that produce a stronger or faster bowel movement, sometimes with pronounced watery stools and cramping. The term comes from the Latin purgare, “to cleanse.” In contrast to milder laxatives, purgatives are more likely to cause significant fluid shifts and abdominal discomfort.

Classification and examples: Purgatives are commonly categorized by their mechanism. Osmotic or saline purgatives—such as magnesium salts and sodium phosphate—draw water into the intestine to promote evacuation. Stimulant or irritant purgatives—such as senna, cascara, aloe, rhubarb, and castor oil—stimulate intestinal motility. Bulk-forming agents and some formulations classified as laxatives tend to be milder and are not always described as purgatives in modern practice. In contemporary bowel-cleansing regimens for procedures, polyethylene glycol-based solutions are used; these are osmotic purgatives in effect and are designed for thorough bowel cleansing.

Medical use and safety: Purgatives are used for relief of constipation when milder treatments fail and for bowel preparation before diagnostic or surgical procedures. They can cause cramps, bloating, dehydration, and electrolyte disturbances, particularly with saline purgatives. They may interact with other medications and are contraindicated in suspected bowel obstruction, certain inflammatory bowel diseases, or gastrointestinal perforation. Long-term or unsupervised use can lead to dependence or reduced colonic function.

Historical context: Purging has roots in humoral medicine, where cleansing of the body was believed to restore balance. Today, purgatives are generally reserved for short-term use and specific clinical indications, under medical guidance.