Types of Laxatives for Constipation

Safety and Effectiveness Compared

Whether you suffer from chronic constipation or just find yourself temporarily bound up, sometimes you need a laxative to get things moving. There are so many different kinds of laxatives available that it can be a little overwhelming when trying to pick the right one. Before making your choice, it is important to know about the safety and effectiveness of each type. 

It's also important to try to determine what condition is causing your constipation. For chronic conditions like irritable bowel syndrome (IBS) or Crohn's disease, some kinds of laxatives can actually make symptoms worse. For occasional constipation, most over-the-counter remedies will do the trick. But for more serious medical conditions, you may want to consult with your healthcare provider before using a laxative.

Fiber Supplements (Bulk Laxatives)

Man reading instructions on pill bottle

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Fiber supplements soften the stool and stimulate a bowel movement. There are three basic types, each of which uses a different ingredient, such as psyllium, calcium polycarbophil, or methylcellulose. Here's a quick overview of them:

  • Psyllium breaks down in the gut and becomes a food source for the good gut bacteria. It's used for a range of conditions, including IBS and diverticulosis (note that it's not recommended for diverticulitis). One big side effect: Psyllium can cause intestinal gas. 
  • Calcium polycarbophil absorbs water in the digestive tract, making stools softer and bulkier. One drawback: It needs to be spaced out with other medications you're taking to ensure they're absorbed properly. 
  • Methylcellulose, like polycarbophil, is plant-based and absorbs water in the gut. It's much less likely to cause intestinal gas than other fiber laxatives.

As with all laxatives, it is essential to drink plenty of fluids while using fiber supplements, or else they could actually worsen constipation.

Fiber supplements can interact with other medications and reduce or delay their effectiveness. Talk with your healthcare provider to ensure your medications are safe to take with a fiber supplement. Some medications that interact with these supplements include antidepressants, diabetes medications, and carbamazepine.

Osmotic Laxatives

Osmotic laxatives work by increasing the amount of fluid secreted within the intestines, resulting in softer and easier-to-pass stools. The three major osmotic laxatives are Miralax, lactulose, and milk of magnesia.

  • Miralax, the brand name for polyethylene glycol PEG, acts similarly to fiber laxatives, as it draws water into the stool making it softer and easier to pass. It also stimulates more frequent bowel movements. Miralax has been found to cause less gas and bloating than other osmotic laxatives. 
  • Lactulose increases the speed of intestinal contractions, stimulating bowel movements. 
  • Milk of magnesia is no longer widely recommended because of the potential complications it may cause for patients with heart or kidney disease. There are safer and more effective options available.

Since osmotic laxatives draw water to the stool, overusing these medications may cause dehydration and electrolyte imbalances. Talk with your healthcare provider to ensure that these laxatives are right for you.

Stimulant Laxatives

Stimulant laxatives work by speeding up the movement of intestinal muscles, thus inducing a bowel movement. Many of the well-known products sold in your drugstore are stimulant laxatives, including Carters Little Pills, ExLax, and Dulcolax.

A stimulant laxative is generally recommended as a short-term treatment for constipation. There is research suggesting that long-term use of these laxatives may be harmful to the colon and increase the risk of cancer.

Check with your healthcare provider before using one of these products, as they can also interact with other over-the-counter and prescription medications. 

Herbal Stimulant Laxatives

There are many different herbs that have a reputation for having laxative effects. Aloe latex, cascara sagrada, frangula, rhubarb, and senna are all examples of herbal stimulant laxatives.

Herbal laxatives contain anthranoids, chemical compounds that stimulate the intestines, improving motility in the gut (in other words, keeping things moving along more quickly).

Herbal stimulant laxatives are not recommended for long-term use and can cause adverse gastrointestinal effects and other unpredictable reactions. Consult a medical professional before using herbal remedies. 

Stool Softeners

Stool softeners do just what the name suggests: soften the stool so it's easier to pass. They perform many of the same functions as a laxative, but technically aren't laxatives because they don't stimulate the gut. Most stool softeners contain a medication called docusate. Brand names include Colace, Doxinate, and Fleet Sof-Lax.

There are times when a stool softener may be a better option than a laxative to relieve constipation, especially if you have hemorrhoids or are pregnant (or both). You should consult your healthcare provider to determine which one is the best choice to help you get things moving again. 

Note that there is limited evidence to support the effectiveness of stool softeners. However, some people find stool softeners to be helpful, and because they are generally well-tolerated, they are a safe option to try.

Stool softeners are recommended for short-term use, but you can use them for longer periods if your healthcare provider gives you the green light.

Choosing a Laxative

Knowing which laxative to choose may seem difficult. But the American Gastroenterological Association recommends using a fiber supplement as the first treatment approach for constipation.

If fiber supplements do not help, osmotic laxatives should be the next approach considered. Stimulant laxatives are recommended if osmotic laxatives fail to be of benefit.

There is limited evidence on the effectiveness of herbal stimulant laxatives, but some find them to be helpful. Talk with your healthcare provider to see if a herbal remedy is safe for you, as some herbal laxatives may be unsafe for those with certain health conditions.

For example, senna products are not suitable for those with liver and kidney diseases due to their possible toxicity to the liver and kidney.

Frequently Asked Questions

  • Can laxatives make constipation worse?

    Yes, using laxatives too often can make the intestines dependent on the medication. Thus, you will be more likely to experience constipation if you don’t continue using the laxatives. If you stop taking the laxative, you may experience constipation again. 

  • What is the difference between MiraLax and milk of magnesia?

    Both are used as laxatives and work by softening stool. However, they have different compositions. Milk of magnesia is a form of magnesium hydroxide. MiraLax contains polyethylene glycol, a compound derived from petroleum. With MiraLax, it can take one to three days to become regular. Milk of magnesia may cause a bowel movement within a half hour to six hours. Long-term use of magnesium laxatives like milk of magnesia is not recommended. 

  • How can I relieve constipation naturally?

    Drinking 8 to 10 cups of water or liquid daily, eating more fiber such as fruit with skins, and being active are the most effective ways to relieve minor constipation and stay regular. You can also use psyllium, natural plant-based fiber. Some herbs can stimulate a bowel movement. These may have side effects or interact with other medications, so always discuss them with your healthcare provider.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Barbara Bolen, PhD
Barbara Bolen, PhD, is a licensed clinical psychologist and health coach. She has written multiple books focused on living with irritable bowel syndrome.