How Quickly Do Laxatives Work?

When time is of the essence, laxatives are an effective, safe way of resolving chronic and independent bouts of constipation. And depending on the individual, different types of laxatives can be used, such as hyperosmotic or emollient. Read on to learn about how different types of laxatives work for constipation.

January 17, 2025 · 14 min · 2895 words · Patricia Sanders

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Table of ContentsView AllTable of ContentsLaxatives for Constipation TreatmentHow Quickly Do Laxatives Work?Different Types of LaxativesWhen to Avoid LaxativesAlternative Treatment OptionsFrequently Asked Questions

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Table of Contents

Laxatives for Constipation Treatment

How Quickly Do Laxatives Work?

Different Types of Laxatives

When to Avoid Laxatives

Alternative Treatment Options

Frequently Asked Questions

Laxatives belong to different classes and work in several ways to improve bowel movements. Some commonly used laxatives include MiraLax (polyethylene glycol), Dulcolax (bisacodyl), and Metamucil (psyllium).

Thesymptoms of constipationusually ease within a few days after using these or similar products.

However, if OTC medications are not alleviating the symptoms, call your healthcare provider for a prescription laxative.

Different types of laxatives vary in how quickly they begin working, dosing regimens, how they’re administered, and how long they take to exit the body.

This article below will discuss different types of laxatives, how they work, and how long they last in your system.

Getty Images / Photography.

How long do laxatives work?

An everyday use oflaxativestreats constipation, a common gastrointestinal (GI) problem prevalent worldwide. Usually, common laxatives are given orally or via the rectal route of administration.

Mostly, constipation is not a severe issue and typically does not last long. However, there are some cases where it can become a chronic problem.

In such cases, laxatives can treat chronic constipation, a complicated condition among older individuals with difficult and recurring stool passage.

Chronic constipation affects up to 20% of the population. It can significantly negatively impact the quality of life and causes significant psychological distress.

When non-medical management is ineffective, laxatives can be a reliable drug choice. Different types of laxatives are available with other active ingredients and dosage forms.

Overall, laxatives are an effective, safe way of resolving constipation.

However, they can carry different active ingredients and mechanisms of action (the way a drug works inside the body). Additionally, how quickly a laxative begins to work and for how long it works may vary.

Specifically, the difference in the time a medication takes to start work or stay in your system depends on various factors. These can be active ingredients, the dose given, and the route of elimination.

For example, MiraLax is an orally administered, brand-name medication that increases bowel movements and softens the stool so it is easier to pass. For the successful use of this drug, however, it should be taken every day as needed for up to two weeks.

Metamucil, also orally administered, is a laxative that absorbs liquid in the intestines and instigates swelling to create a “bulky” stool, thus making it easier to pass. It should be taken one to three times daily to achieve its intended effect.

In the case of both drugs, failure to skip doses or take the medication at the wrong time can directly impact the laxative’s ability to work.

Your pharmacist or healthcare provider can help determine which laxative best suits you or a loved one.

Depending on a person’s medical history, current condition, or ability to tolerate one drug over another, a healthcare provider may recommend one of several different types of laxatives.

Below outlines the four major types of laxatives and how they’re used to manage constipation.

Bulk-Forming Laxatives

For decades, within Western society, constipation has been associated with a deficiency of dietary fiber. Dietary fiber effectively relieves mild to moderate, but not severe, constipation.

Typically, recommended dietary fiber intake is 20 to 35 grams (g) daily.

Bulk laxatives work similarly to the fiber present in a person’s diet. Fiber foods include whole wheat bread, unrefined cereals, and vegetables.

Bulk laxatives promote the absorption of water into the bowels. In some people, these agents also delay gastric (stomach) emptying and depress appetite. Bulk laxatives also carry the ability to delay feelings of hunger.

Bulk laxatives make stools larger and softer, making them easier to pass. They take 12 to 24 hours to start producing effect and 48 to 72 hours for their full effect.

Some commonly used brands of bulk laxatives include:

Emoliant Laxatives

Stool softeners are used on a short-term basis to relieve constipation. They help reduce people’s strain during bowel movements because of heart conditions, hemorrhoids, and other medical problems.

Docusate sodium is a commonly used stool softener, a detergent agent that activates small and large intestine fluid discharge.

Common brand names available are:

Hyperosmotic Laxatives

There are several different types of hyperosmotic laxatives with other active ingredients:

Lactulose: The active ingredient in lactulose laxatives is a sugar-like compound. It breaks down in the bowel into substances that pull water out from the body to add into the bowel to soften the stool and make it easier to pass.

Lactulose laxatives are often used for the treatment of long-term or chronic constipation. The onset of action takes 24 to 72 hours, longer than other osmotic laxatives.

Examples of lactulose laxative products include the brand-name product, Generlac.

Saline: These laxatives contain salts in liquid and are used as a short-term treatment for constipation. Saline takes 30 minutes to three hours to work. Examples of saline laxatives include Phillips’ Milk of Magnesia.

It gives watery diarrhea to ease the passage of stool from the colon. PEG-ES also contains electrolytes to prevent dehydration and other serious side effects from fluid loss as the colon empties. It may take two to four days to produce a bowel movement.

Some brand-name products that contain PEG-ES include:

One such brand-name example of a medication that contains PEG-3350 is MiraLax.

Notably, one study found PEG-3350 more effective than lactulose in treating chronic constipation.

Suppositories

Suppositories are dosage forms inserted into body cavities, most commonly the rectum, to deliver drugs to the systemic circulation (part of the vascular system that brings blood from the left ventricle [chamber of the heart] to organs and tissues) or tissues located close to the rectum.

Once inserted, the medication dissolves and enters the bloodstream.

Suppositories can work in different ways depending on their active drug. Usually, bisacodyl and glycerol are given as suppositories to treat constipation.

Bisacodyl is a stimulant laxatives. It stimulates the bowels' muscles, increasing the intestines' activity to cause a bowel movement.

Suppositories can also work to soften the stool to ease stool movement. Generally, laxative suppositories typically cause a bowel movement within 15 to 60 minutes.

Examples of available brand-name suppositories include:

What Are the Differences Between Dulcolax vs. Miralax?

Reference Chart

Use this chart for a general overview of quickly each of the laxatives mentioned above begins working:

Oral and rectal laxatives are usually safe to use, but sometimes laxatives may interact with other medicines or affect the body in certain medical conditions.

Use with caution in the following conditions:

Electrolyte Imbalance: Extended use of some laxatives can lead to an electrolyte imbalance. You can consult a healthcare provider before taking laxatives if you already have an electrolyte imbalance.

Interaction with medications: Laxatives can interact with some antibiotics, heart and bone medications. Ask your healthcare provider before taking laxatives if you are taking these medicines.

Complicating medical conditions:Laxative use can be dangerous if a severe illness, such as appendicitis (inflammation of the appendix) or a bowel obstruction, causes constipation. Frequent use of laxatives for weeks or months can decrease the colon’s ability to contract and worsen constipation.

Children: Don’t give laxatives to children under 6 years old laxatives without asking a healthcare provider.

Pregnancy and Breastfeeding:If pregnant, ask your healthcare provider before using laxatives. Some laxatives, including bulk and stool softeners, are generally safe during pregnancy, but stimulant laxatives may be harmful.

Laxatives are usually safe during breastfeeding, but some ingredients may pass into breast milk and cause diarrhea in nursing infants.

If you’re becoming dependent on laxatives to have a bowel movement, ask your healthcare provider how to gradually stop taking them and restore your colon’s natural ability to contract.

Potential Side Effects

OTC laxatives are pretty common and a safe way to manage constipation. But excessive use of these laxatives may leave you dependent on them for bowel movements.

There may be some side effects of using laxatives.

While using a laxative, contact your healthcare provider if you experience any of the following:

Alternatives to Laxatives

Constipation is sometimes chronic and becomes a critical problem. However, occasionally laxative therapy is not the only treatment for constipation.

Non-medical management that can be helpful includes lifestyle modification, dietary changes, exercise, and laxative therapy.

Lifestyle changes can help manage chronic constipation, such as increasing fluid intake and taking fiber-rich foods such as wheat bran, fresh fruits and vegetables, and oats.

Summary

Constipation makes it difficult for a person to pass stool. It may cause to have three or fewer bowel movements in a week. The stool can be hard, dry, and painful to pass.

In most cases, it lasts a short time and is not severe. One can do many things to prevent constipation, such as eating more fiber, drinking plenty of fluids, increasing mobility, and exercising.

In some cases, the constipation becomes chronic and needs medical management. The first line of management is OTC treatments like laxatives.

There are different kinds of laxatives available that work to provide relief. The time it takes for particular laxatives depends on the active drug, how they work, and the route of administration.

Call your healthcare provider if using laxatives does not relieve the symptoms.

Frequently Asked QuestionsLaxatives are a reliable and standard treatment option for people suffering from constipation. They are effective and safe when used in the recommended dosage.However, research has shown that long-term use of these drugs may have the potential for misuse, abuse, and dependence.According to a scientific study, the average stool frequency is between three per week and three per day.Nonetheless, there can be variations regarding gender, demographics, and genetic makeup.Constipation has been associated with a deficiency of dietary fiber. Dietary fiber effectively relieves mild to moderate, but not severe, constipation.The recommended amount of dietary fiber is 20 to 35 grams per day (g/d), obtained from whole wheat bread, unrefined cereals, citrus fruits, vegetables, and other foods.

Laxatives are a reliable and standard treatment option for people suffering from constipation. They are effective and safe when used in the recommended dosage.However, research has shown that long-term use of these drugs may have the potential for misuse, abuse, and dependence.

Laxatives are a reliable and standard treatment option for people suffering from constipation. They are effective and safe when used in the recommended dosage.

However, research has shown that long-term use of these drugs may have the potential for misuse, abuse, and dependence.

According to a scientific study, the average stool frequency is between three per week and three per day.Nonetheless, there can be variations regarding gender, demographics, and genetic makeup.

According to a scientific study, the average stool frequency is between three per week and three per day.

Nonetheless, there can be variations regarding gender, demographics, and genetic makeup.

Constipation has been associated with a deficiency of dietary fiber. Dietary fiber effectively relieves mild to moderate, but not severe, constipation.The recommended amount of dietary fiber is 20 to 35 grams per day (g/d), obtained from whole wheat bread, unrefined cereals, citrus fruits, vegetables, and other foods.

Constipation has been associated with a deficiency of dietary fiber. Dietary fiber effectively relieves mild to moderate, but not severe, constipation.

The recommended amount of dietary fiber is 20 to 35 grams per day (g/d), obtained from whole wheat bread, unrefined cereals, citrus fruits, vegetables, and other foods.

21 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Institute of Diabetes and Digestive and Kidney Diseases.Treatment for constipation.Forootan M, Bagheri N, Darvishi M.Chronic constipation.Medicine (Baltimore). 2018;97(20):e10631. doi:10.1097/MD.0000000000010631Portalatin M, Winstead N.Medical management of constipation.Clin Colon Rectal Surg. 2012;25(1):12-19. doi:10.1055/s-0032-1301754Rao SSC, Brenner DM.Efficacy and safety of over-the-counter therapies for chronic constipation: an updated systematic review.Am J Gastroenterol. 2021;116(6):1156-1181. doi:10.14309/ajg.0000000000001222MedlinePlus.Polyethylene glycol 3350.MedlinePlus.Psyllium.Barber TM, Kabisch S, Pfeiffer AFH, Weickert MO.The health benefits of dietary fibre.Nutrients. 2020;12(10):3209. doi:10.3390/nu12103209DailyMed.Label: FiberCon- calcium polycarbophil tablet.DailyMed.Label: Citrucel- methylcellulose powder, for solution.MedlinePlus.Stool softeners.MedlinePlus.Lactulose.DailyMed.Label: Phillips Fresh Mint Milk of Magnesia liquid.MedlinePlus.Polyethylene glycol-electrolyte solution (PEG-ES).Dheivamani N, Thomas W, Bannerjii R, Mukherjee M, Mitra M.Efficacy of polyethylene glycol 3350 as compared to lactulose in treatment of ROME IV criteria-defined pediatric functional constipation: a randomized controlled trial.Indian J Gastroenterol. 2021;40(2):227-233. doi:10.1007/s12664-021-01148-wHua S.Physiological and pharmaceutical considerations for rectal drug formulations.Front Pharmacol.2019;10:1196. doi:10.3389/fphar.2019.01196.MedlinePlus.Rectal bisacodyl.Prescribers Digital Reference.Polyethylene glycol 3350 - drug summary.Prescribers' Digital Reference.Lactulose - drug summary.National Institute of Diabetes and Digestive Kidney Disease.Eating, diet, & nutrition for constipation.Roerig JL, Steffen KJ, Mitchell JE, Zunker C.Laxative abuse: epidemiology, diagnosis and management.Drugs. 2010;70(12):1487-1503. doi:10.2165/11898640-000000000-00000Walter SA, Kjellström L, Nyhlin H, Talley NJ, Agréus L.Assessment of normal bowel habits in the general adult population: the Popcol study.Scand J Gastroenterol.2010;45(5):556-566. doi:10.3109/00365520903551332

21 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Institute of Diabetes and Digestive and Kidney Diseases.Treatment for constipation.Forootan M, Bagheri N, Darvishi M.Chronic constipation.Medicine (Baltimore). 2018;97(20):e10631. doi:10.1097/MD.0000000000010631Portalatin M, Winstead N.Medical management of constipation.Clin Colon Rectal Surg. 2012;25(1):12-19. doi:10.1055/s-0032-1301754Rao SSC, Brenner DM.Efficacy and safety of over-the-counter therapies for chronic constipation: an updated systematic review.Am J Gastroenterol. 2021;116(6):1156-1181. doi:10.14309/ajg.0000000000001222MedlinePlus.Polyethylene glycol 3350.MedlinePlus.Psyllium.Barber TM, Kabisch S, Pfeiffer AFH, Weickert MO.The health benefits of dietary fibre.Nutrients. 2020;12(10):3209. doi:10.3390/nu12103209DailyMed.Label: FiberCon- calcium polycarbophil tablet.DailyMed.Label: Citrucel- methylcellulose powder, for solution.MedlinePlus.Stool softeners.MedlinePlus.Lactulose.DailyMed.Label: Phillips Fresh Mint Milk of Magnesia liquid.MedlinePlus.Polyethylene glycol-electrolyte solution (PEG-ES).Dheivamani N, Thomas W, Bannerjii R, Mukherjee M, Mitra M.Efficacy of polyethylene glycol 3350 as compared to lactulose in treatment of ROME IV criteria-defined pediatric functional constipation: a randomized controlled trial.Indian J Gastroenterol. 2021;40(2):227-233. doi:10.1007/s12664-021-01148-wHua S.Physiological and pharmaceutical considerations for rectal drug formulations.Front Pharmacol.2019;10:1196. doi:10.3389/fphar.2019.01196.MedlinePlus.Rectal bisacodyl.Prescribers Digital Reference.Polyethylene glycol 3350 - drug summary.Prescribers' Digital Reference.Lactulose - drug summary.National Institute of Diabetes and Digestive Kidney Disease.Eating, diet, & nutrition for constipation.Roerig JL, Steffen KJ, Mitchell JE, Zunker C.Laxative abuse: epidemiology, diagnosis and management.Drugs. 2010;70(12):1487-1503. doi:10.2165/11898640-000000000-00000Walter SA, Kjellström L, Nyhlin H, Talley NJ, Agréus L.Assessment of normal bowel habits in the general adult population: the Popcol study.Scand J Gastroenterol.2010;45(5):556-566. doi:10.3109/00365520903551332

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

National Institute of Diabetes and Digestive and Kidney Diseases.Treatment for constipation.Forootan M, Bagheri N, Darvishi M.Chronic constipation.Medicine (Baltimore). 2018;97(20):e10631. doi:10.1097/MD.0000000000010631Portalatin M, Winstead N.Medical management of constipation.Clin Colon Rectal Surg. 2012;25(1):12-19. doi:10.1055/s-0032-1301754Rao SSC, Brenner DM.Efficacy and safety of over-the-counter therapies for chronic constipation: an updated systematic review.Am J Gastroenterol. 2021;116(6):1156-1181. doi:10.14309/ajg.0000000000001222MedlinePlus.Polyethylene glycol 3350.MedlinePlus.Psyllium.Barber TM, Kabisch S, Pfeiffer AFH, Weickert MO.The health benefits of dietary fibre.Nutrients. 2020;12(10):3209. doi:10.3390/nu12103209DailyMed.Label: FiberCon- calcium polycarbophil tablet.DailyMed.Label: Citrucel- methylcellulose powder, for solution.MedlinePlus.Stool softeners.MedlinePlus.Lactulose.DailyMed.Label: Phillips Fresh Mint Milk of Magnesia liquid.MedlinePlus.Polyethylene glycol-electrolyte solution (PEG-ES).Dheivamani N, Thomas W, Bannerjii R, Mukherjee M, Mitra M.Efficacy of polyethylene glycol 3350 as compared to lactulose in treatment of ROME IV criteria-defined pediatric functional constipation: a randomized controlled trial.Indian J Gastroenterol. 2021;40(2):227-233. doi:10.1007/s12664-021-01148-wHua S.Physiological and pharmaceutical considerations for rectal drug formulations.Front Pharmacol.2019;10:1196. doi:10.3389/fphar.2019.01196.MedlinePlus.Rectal bisacodyl.Prescribers Digital Reference.Polyethylene glycol 3350 - drug summary.Prescribers' Digital Reference.Lactulose - drug summary.National Institute of Diabetes and Digestive Kidney Disease.Eating, diet, & nutrition for constipation.Roerig JL, Steffen KJ, Mitchell JE, Zunker C.Laxative abuse: epidemiology, diagnosis and management.Drugs. 2010;70(12):1487-1503. doi:10.2165/11898640-000000000-00000Walter SA, Kjellström L, Nyhlin H, Talley NJ, Agréus L.Assessment of normal bowel habits in the general adult population: the Popcol study.Scand J Gastroenterol.2010;45(5):556-566. doi:10.3109/00365520903551332

National Institute of Diabetes and Digestive and Kidney Diseases.Treatment for constipation.

Forootan M, Bagheri N, Darvishi M.Chronic constipation.Medicine (Baltimore). 2018;97(20):e10631. doi:10.1097/MD.0000000000010631

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

Rao SSC, Brenner DM.Efficacy and safety of over-the-counter therapies for chronic constipation: an updated systematic review.Am J Gastroenterol. 2021;116(6):1156-1181. doi:10.14309/ajg.0000000000001222

MedlinePlus.Polyethylene glycol 3350.

MedlinePlus.Psyllium.

Barber TM, Kabisch S, Pfeiffer AFH, Weickert MO.The health benefits of dietary fibre.Nutrients. 2020;12(10):3209. doi:10.3390/nu12103209

DailyMed.Label: FiberCon- calcium polycarbophil tablet.

DailyMed.Label: Citrucel- methylcellulose powder, for solution.

MedlinePlus.Stool softeners.

MedlinePlus.Lactulose.

DailyMed.Label: Phillips Fresh Mint Milk of Magnesia liquid.

MedlinePlus.Polyethylene glycol-electrolyte solution (PEG-ES).

Dheivamani N, Thomas W, Bannerjii R, Mukherjee M, Mitra M.Efficacy of polyethylene glycol 3350 as compared to lactulose in treatment of ROME IV criteria-defined pediatric functional constipation: a randomized controlled trial.Indian J Gastroenterol. 2021;40(2):227-233. doi:10.1007/s12664-021-01148-w

Hua S.Physiological and pharmaceutical considerations for rectal drug formulations.Front Pharmacol.2019;10:1196. doi:10.3389/fphar.2019.01196.

MedlinePlus.Rectal bisacodyl.

Prescribers Digital Reference.Polyethylene glycol 3350 - drug summary.

Prescribers' Digital Reference.Lactulose - drug summary.

National Institute of Diabetes and Digestive Kidney Disease.Eating, diet, & nutrition for constipation.

Roerig JL, Steffen KJ, Mitchell JE, Zunker C.Laxative abuse: epidemiology, diagnosis and management.Drugs. 2010;70(12):1487-1503. doi:10.2165/11898640-000000000-00000

Walter SA, Kjellström L, Nyhlin H, Talley NJ, Agréus L.Assessment of normal bowel habits in the general adult population: the Popcol study.Scand J Gastroenterol.2010;45(5):556-566. doi:10.3109/00365520903551332

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