What are Gastrointestinal (GI) cathartics?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: March 11, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

Gastrointestinal (GI) cathartics are medications or agents used to evacuate the bowels, primarily for bowel preparation before procedures like CT colonography or colonoscopy, and can include polyethylene glycol electrolyte solution, oral sodium phosphate-based agents, and magnesium citrate. These agents are crucial for effective bowel cleansing and are selected based on patient factors and physician preferences 1. The choice of cathartic agent depends on various factors, including the patient's underlying conditions, potential contraindications for electrolyte shifts, fluid shifts, or phosphate ingestion.

Some of the commonly used GI cathartics include:

  • Polyethylene glycol electrolyte solution, a nonabsorbable, osmotically balanced preparation that is safe and results in little fluid shifting during administration
  • Oral sodium phosphate-based agents, which are easier to ingest for many patients but can result in electrolyte shifts when doses exceeding 45 mL daily are employed
  • Magnesium citrate, a milder saline cathartic preparation that performs similarly to polyethylene glycol for CT colonography when combined with fecal tagging agents 1.

It is essential to note that the selection of a cathartic agent should be based on individual patient needs and factors, and the use of these agents should be guided by evidence-based recommendations to ensure effective and safe bowel preparation 1. Additionally, the use of fecal and fluid tagging agents, such as barium suspension or iodinated oral contrast agents, can help improve the accuracy of diagnostic procedures like CT colonography by reducing false-positive examinations and permitting identification of submerged polyps 1.

From the FDA Drug Label

Uses for relief of occasional constipation (irregularity). This product generally produces bowel movement in 12 to 72 hours. USE • relieves occasional constipation (irregularity) • generally produces a bowel movement in 1 to 3 days

Gastrointestinal (GI) cathartics are not directly defined in the provided drug labels. However, based on the information given, the drugs mentioned (psyllium and polyethylene glycol) are used for relief of occasional constipation and produce a bowel movement.

  • The provided drug labels do not explicitly define GI cathartics, but they describe the use of certain products for constipation relief 2 3. The FDA drug label does not answer the question.

From the Research

Definition of Gastrointestinal (GI) Cathartics

  • Gastrointestinal (GI) cathartics are a type of laxative that stimulates bowel movements and helps relieve constipation 4.
  • They work by increasing the amount of water in the intestines, softening stool, and stimulating the intestinal muscles to move stool through the digestive system.

Types of GI Cathartics

  • Stimulant cathartics: These laxatives stimulate the intestinal muscles to move stool through the digestive system 4, 5.
  • Saline laxatives: These laxatives work by drawing water into the intestines to soften stool 4.
  • Hyperosmotic laxatives: These laxatives draw water into the intestines to soften stool and stimulate bowel movements 4, 6.
  • Bulk-forming laxatives: These laxatives absorb water and expand, forming a bulky stool that is easy to pass 7, 4.

Use of GI Cathartics

  • GI cathartics are commonly used to treat constipation in adults and children 7, 4, 5, 6, 8.
  • They are often used in combination with dietary changes, such as increasing fiber and fluid intake, and lifestyle modifications, such as regular exercise and scheduled toileting 7, 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Use and abuse of laxatives.

American journal of hospital pharmacy, 1977

Research

Management of Constipation in Older Adults.

American family physician, 2015

Research

Use of polyethylene glycol in functional constipation and fecal impaction.

Revista espanola de enfermedades digestivas, 2016

Research

Treatment of constipation in the elderly.

Postgraduate medicine, 1988

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.