Guide to Over-the-Counter Laxatives

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Many laxatives are available as over-the-counter (OTC) 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 disruption of metabolite levels (body salts), dehydration, kidney injury, and even death.

How to Relieve Constipation

Instead of buying an over-the-counter laxative to help with intermittent constipation, you should first try a high-fiber diet, increased 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.

Laxative Types

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.

Over-the-counter bulk laxative brands include:

  • 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).

Over-the-counter stool softeners include:

  • 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 a 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.

Studies have shown that long-term use of stool softeners can result in (fat-soluble) vitamin A, D, E and K deficiencies.

Stimulant Laxatives

It is not fully 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.

Examples of OTC stimulant laxatives include:

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

Osmotic Laxatives

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

Osmotic laxatives are considered effective but if overused may cause problems with your body’s water and electrolyte balance.

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

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

Sodium Phosphate Osmotic Laxatives

Phosphate laxatives are absorbed by the small intestine and have an osmotic effective to soften stool making it easer to pass. A high dose must be ingested to produce an osmotic laxative effect.

In January 2014, the US Food and Drug Administration (FDA) released a safety warning about over the counter sodium phosphate osmotic laxatives. They warned that in rare instances, taking more than one dose in 24 hours could cause serious harm to the kidneys and heart, and even death.

According to the FDA, "laxative products containing sodium phosphates are marketed under the brand name "Fleet" and also as store brands and generic products. All of them are potentially associated with serious side effects, such as dehydration and/or abnormal levels of electrolytes in the blood that can lead to serious complications, such as kidney damage and sometimes death."

The FDA suggests speaking to your healthcare provider before taking this type of laxative and to watch for warning signs warning signs of a bad reaction. 

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.

A Word From Verywell

One of the worst things you can do with laxatives is to use them as long-term 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.

Please keep in mind that—as with all medications—it's better to prevent a problem in the first place than it is to take medications to treat it. If you experience constipation, it's a good idea to meet with your physician and discuss diet, fluids, exercise, and toileting habits. Lifestyle changes can often help relieve constipation and obviate the need for laxatives.

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Article Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial policy to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Jin J. Over-the-counter Laxatives. JAMA. 2014;312(11):1167. doi:10.1001/jama.2014.2078

  2. Portalatin M, Winstead N. Medical management of constipation. Clin Colon Rectal Surg. 2012;25(1):12–19. doi:10.1055/s-0032-1301754

  3. Use Certain Laxatives With Caution. U.S. Food and Drug Administration (FDA). January 1, 2014.

Additional Reading

  • Acosta A, Tangalos EG, Harari D. Constipation. In: Halter JB, Ouslander JG, Studenski S, High KP, Asthana S, Supiano MA, Ritchie C. eds. Hazzard's Geriatric Medicine and Gerontology, 7e New York, NY: McGraw-Hil.

  • 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.