What medication can help increase stool bulk?

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Last updated: May 24, 2025View editorial policy

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From the Guidelines

To help bulk stool, I recommend fiber supplements like psyllium husk or methylcellulose, as they are safe and effective in improving stool viscosity and transit time, according to the most recent guidelines 1. When choosing a fiber supplement, consider options like psyllium husk (Metamucil) or methylcellulose (Citrucel), which are well-tolerated and can be taken during pregnancy without systemic absorption 1. Some key points to consider when taking fiber supplements include:

  • Starting with a low dose, typically 1 teaspoon or 1 tablet once daily, and gradually increasing to the recommended amount on the package (usually 1-2 teaspoons or tablets 1-3 times daily) mixed with at least 8 ounces of water
  • Increasing overall fluid intake throughout the day to help the fiber supplements work effectively
  • Aiming for 25-30 grams of fiber daily through a combination of supplements and dietary changes
  • Being aware that it may take a few days to notice improvement, and some people may experience temporary bloating or gas when first starting fiber supplements
  • Consulting a healthcare provider if symptoms worsen or don't improve after two weeks, as there may be underlying issues requiring different treatment 1. Other options for bulking stool include unprocessed wheat bran, ispaghula, and sterculia, however, the most recent and highest quality study recommends psyllium husk or methylcellulose 1. It's essential to note that stimulant laxatives should be avoided due to conflicting safety data 1, and instead, focus on bulk-forming agents and osmotic laxatives like polyethylene glycol or lactulose, which can be administered safely during pregnancy 1.

From the FDA Drug Label

Purpose Bulk-forming fiber laxative Principal Display Panel ... Gives you additional fiber to help relieve occasional constipation Medications to help bulk stool include:

  • Methylcellulose (PO) 2, 2 Bulk-forming fiber laxatives like methylcellulose work by adding bulk to the stool, making it easier to pass. Methylcellulose is a fiber therapy that can help relieve occasional constipation by adding fiber to the diet.

From the Research

Medication to Help Bulk Stool

To help bulk stool, several medications and supplements can be used. The following are some options:

  • Psyllium: a bulk-forming agent that can help increase stool water content and improve symptoms of constipation 3, 4, 5, 6, 7
  • Methylcellulose: a bulk-forming agent that can help improve symptoms of constipation 3
  • Polycarbophil: a bulk-forming agent that can help improve symptoms of constipation 3
  • Polyethylene glycol: an osmotic laxative that can help increase stool water content and improve symptoms of constipation 3, 5
  • Linaclotide or lubiprostone: medications that can help improve symptoms of constipation, particularly in patients who do not respond to other treatments 3

Mechanism of Action

These medications and supplements work by:

  • Increasing stool water content: psyllium, methylcellulose, and polycarbophil absorb water and expand, helping to soften and bulk the stool 4, 6
  • Increasing stool frequency: psyllium, polyethylene glycol, and other laxatives can help increase the frequency of bowel movements 5, 7
  • Improving stool consistency: psyllium and other bulk-forming agents can help improve the consistency of the stool, making it easier to pass 7

Efficacy and Safety

The efficacy and safety of these medications and supplements have been studied in several clinical trials:

  • Psyllium has been shown to be effective in improving symptoms of constipation, including stool frequency and consistency 4, 6, 7
  • Polyethylene glycol has been shown to be effective in improving symptoms of constipation, including stool frequency and consistency 3, 5
  • Methylcellulose and polycarbophil have been shown to be effective in improving symptoms of constipation, although the evidence is limited 3
  • Linaclotide and lubiprostone have been shown to be effective in improving symptoms of constipation, particularly in patients who do not respond to other treatments 3

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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