How is propylene glycol (PG) taken for the treatment of constipation?

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From the Guidelines

Propylene glycol is not typically used for constipation treatment, instead, polyethylene glycol (PEG) is the recommended medication for constipation, with a standard adult dose of 17 grams dissolved in 8 ounces of water, taken once daily, as supported by the most recent study 1.

Key Points

  • Polyethylene glycol (PEG) is the recommended medication for constipation, not propylene glycol.
  • The standard adult dose of PEG is 17 grams (about 1 heaping tablespoon) dissolved in 8 ounces of water, juice, or another beverage, taken once daily.
  • PEG works as an osmotic laxative by drawing water into the intestines, softening stool and making it easier to pass.
  • Relief typically occurs within 24-72 hours, and PEG is generally well-tolerated with minimal side effects.
  • PEG can be used for both short-term relief and long-term management of chronic constipation, as shown in a study published in 2023 1.

Important Considerations

  • For children, dosing should be determined by a healthcare provider.
  • If constipation persists after several days of treatment, you should consult a healthcare provider.
  • The American Gastroenterological Association and the American College of Gastroenterology recommend the use of PEG for the management of chronic idiopathic constipation, as stated in their clinical practice guideline 1.

Evidence Summary

  • A 2023 study published in Gastroenterology found that PEG is effective in treating chronic constipation, with a dose of 17 grams per day being well-tolerated and effective in promoting laxation 1.
  • The study included 304 participants with chronic constipation and found that PEG significantly improved bowel movements and reduced symptoms of constipation.
  • The evidence supports the use of PEG as a first-line treatment for constipation, due to its efficacy, safety, and tolerability, as noted in the study 1.

From the FDA Drug Label

Directions As a dietary supplement for adults, take two (2) drops orally once daily, or as directed by a healthcare provider. The dropper supplied delivers approximately 40 drops per mL. The FDA drug label does not answer the question.

From the Research

Treatment of Constipation with Polyethylene Glycol

The provided studies do not mention the use of propylene glycol for constipation. However, they do discuss the use of polyethylene glycol (PEG) as a treatment for constipation.

  • Polyethylene glycol is an effective treatment for chronic constipation, with studies showing it to be more effective than lactulose in outcomes such as stool frequency per week, form of stool, relief of abdominal pain, and the need for additional products 2, 3.
  • PEG is also effective in the treatment of fecal impaction, with one study showing it to be as efficacious as enemas in treating fecal impaction 4.
  • The efficacy and safety of PEG have been evaluated in several studies, with results showing it to be a highly effective and well-tolerated therapy for the treatment of severe constipation and fecal impaction 5.
  • Long-term use of PEG has also been studied, with one open-label study showing it to be safe and effective for treating constipation in adult and elderly patients for periods up to 12 months 6.

Dosage and Administration

  • The dosage of PEG used in the studies varied, with one study using up to eight 13.8 g sachets of PEG+E (polyethylene glycol plus electrolytes) per day 5.
  • Another study used a single daily dose of 17 g of polyethylene glycol 3350 for 12 months 6.
  • The studies do not provide information on the use of propylene glycol for constipation, and it is not clear if it is effective or safe for this use.

Safety and Efficacy

  • The studies provide evidence for the safety and efficacy of PEG in the treatment of constipation, but do not provide information on the use of propylene glycol for this condition.
  • The safety profile of PEG is generally good, with gastrointestinal complaints such as diarrhea, loose stool, flatulence, and nausea being the most common adverse effects 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Lactulose versus Polyethylene Glycol for Chronic Constipation.

The Cochrane database of systematic reviews, 2010

Research

A literature review of two laxatives: lactulose and polyethylene glycol.

British journal of community nursing, 2011

Research

Use of polyethylene glycol in functional constipation and fecal impaction.

Revista espanola de enfermedades digestivas, 2016

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.

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