Guide to Over-the-Counter Laxatives

Which laxative is right for you?

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Many laxatives are available as over-the-counter medications, and people often misuse them. Most people who use laxatives don't need them, and long-term use of laxatives can have serious health repercussions like derangement of metabolites (body salts), dehydration, kidney injury and even death. 

Instead of buying an over-the-counter laxative to help with intermittent constipation, you should first try a high-fiber diet, fluid intake, regular exercise and practice proper bathroom hygiene.

More specifically, you should use the bathroom when you feel the urge and refrain from "holding it in." If these measures fail to work, you should meet with a physician to discuss laxative use especially if you plan to take laxatives for more than a day or two.

Over-the-counter laxatives are classified according to four main principal mechanisms of action:

Of note, some of these laxatives work by some combination of these mechanisms.

Bulk-Forming Laxatives

As their name indicates, bulk-forming laxatives work by bulking up your stool. These laxatives are made of indigestible particles (colloid) which absorb water. Once bulk laxatives absorb water, they cause distension of the bowel and trigger bowel movement via wave-like muscle contractions (peristalsis). 

Bulk laxatives are commonly made of plant fibers like methylcellulose. When the bacteria that live in your gut digest these plant fibers, excess flatus and bloating can result.


Here are some over-the-counter bulk laxatives:

  • FiberCon (polycarbophil)
  • Citrucel (methylcellulose)
  • Metamucil (psyllium)
  • Konsyl (psyllium)

Stool Softeners

Stool softeners or stool surfactant agents work by permitting water and fat to suffuse your stool and thus soften it. Stool softeners can be taken by mouth or rectally (think Fleet suppositories or Fleet enemas).


Here are some over-the-counter stool softeners:

  • Colace (docusate)
  • Surfak (docusate)
  • Phillips' Stool Softener Liquid Gels (docusate)
  • mineral oil
  • Pedia-lax (glycerin suppository)

Of note, mineral oil is commonly used to lubricate stool in children and adults with debilitating disability. In order to be palatable, mineral oil needs to be mixed with juice. Additionally, docusate and glycerin suppositories are commonly prescribed in an inpatient or hospital setting to prevent constipation.

Please keep in mind that long-term use of stool softeners can result in (fat-soluble) vitamin A, D, E and K deficiencies

Stimulant Laxatives

Truth be told, we still poorly understand exactly how stimulant laxatives or cathartics work. We know that they directly stimulate the intestinal nervous system as well as cause electrolyte and fluid secretion by the colon. 

For some time, physicians have worried that long-term use of stimulant laxatives could lead to patient dependence on these medications. Furthermore, physicians have worried that these laxatives could damage the nervous system of the intestines (myenteric plexus).

Recent research, however, suggests that long-term use of stimulant laxatives is probably safe. Nevertheless, the only people who should be taking these laxatives for long periods of time are hospitalized patients or patients in long-term care facilities with neurological impairment and inability to leave the bed.

Here are some examples of OTC stimulant laxatives:

  • Dulcolax (bisacodyl)
  • Fleet bisacodyl
  • Senokot (senna)
  • cascara
  • Ex-Lax (sennosides)
  • castor oil
  • aloe

Osmotic Laxatives

Osmotic laxatives are nonabsorbable compounds and soluble compounds that draw fecal water into the colon via osmosis. In this way, osmotic laxatives liquefy your stool.

Here are some examples of over-the-counter osmotic laxatives:

  • milk of magnesia (magnesium hydroxide)
  • sorbitol
  • MiraLax (polyethylene glycol)

Please keep in mind that laxatives are best used as short-term relief, and you should consult with your physician before you use them. Never give a child a laxative without speaking with a pediatrician first.

One of the worst things you can do with laxatives is to use them as chronic self-treatment for some more serious medical condition and thus mask a problem that needs immediate attention. For example, colon cancer can cause constipation by way of obstruction.

Selected Sources

McQuaid KR. Drugs Used in the Treatment of Gastrointestinal Diseases. In: Katzung BG, Trevor AJ. eds. Basic & Clinical Pharmacology, 13e. New York, NY: McGraw-Hill; 2015. Accessed June 09, 2015.

FDA document titled "Use Certain Laxatives With Caution" dated 1/8/2014.  Accessed on 6/9/2015.

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