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What are laxatives?

Laxatives are a type of medicine that can help you empty your bowels if you are having trouble going to the toilet.

They are widely used to treat constipation and are available over the counter (without a prescription or 'OTC') from pharmacies and supermarkets.

Things to consider

Just because laxatives are available over the counter does not mean they are safe and suitable for everyone.

Laxatives are not usually recommended for children unless advised by a doctor and some types of laxatives may not be safe to use if you have a bowel condition such as Crohn’s disease or ulcerative colitis.

You should always read carefully the patient information leaflet that comes with medication to make sure it is safe for you to take.

Read more about the considerations regarding laxatives.

Types of laxatives

The four most widely used laxatives are:

  • osmotic laxatives which make your stools (‘poo’) softer by increasing the amount of water in your bowels
  • stimulant laxatives which speed up the movement of your bowel by stimulating the muscles that line your digestive tract
  • bulk-forming laxatives, also known as fibre supplements, work in the same way as dietary fibre; they increase the bulk of your stools by helping your stools retain fluid
  • stool softener laxatives add water to your stools to lubricate them, making them more slippery and easier to pass

Less commonly used types of laxatives include:

  • bowel cleansing solutions – these are often given to people who are going to have bowel surgery or a bowel examination to make sure that the bowel is empty and are not seen as a routine treatment for constipation
  • peripheral opioid-receptor antagonists– these are used to treat constipation in people who are terminally ill where the constipation is the result of taking powerful painkiller medications such as morphine
  • prucalopride – used to treat persistent constipation in women who have failed to respond to treatment (it is unclear whether prucalopride is safe or effective in men so its use in men is currently not recommended)


Laxatives are available as:

  • tablets or capsules you swallow
  • sachets of powder you mix with water and then drink
  • suppositories – a capsule you place inside your rectum (back passage) where it will dissolve

Ideally, laxatives should only be used for short periods of time as prolonged use can make your body dependent on them, so your bowel no longer functions normally without them.

Recommendations can vary depending on the type of laxative but generally it is recommended that you do not take laxatives for more than 5-7 days in a row. If symptoms persist after this time contact your doctor for advice.

You should take a laxative with plenty of water as this can help prevent unpleasant side effects.

Read more information about the dosage of laxatives.

Side effects

Common side effects of laxatives include:

  • flatulence (breaking wind or ‘farting’)
  • bloating
  • abdominal pain

These side effects are usually mild and should pass once you stop taking the laxatives.

The long-term use of laxatives can cause more troublesome side effects such as:

  • dehydration
  • unbalanced levels of salts and minerals in your body

Read more about the side effects of laxatives.


In many cases you can improve the symptoms of constipation without having to use laxatives through lifestyle changes, such as:

  • increase your daily intake of fibre - you should eat at least 18-30g of fibre a day; high-fibre foods include fruit, vegetables and cereals
  • add bulking agents, such as wheat bran, to your diet - these will help make your stools softer and easier to pass.
  • drink plenty of water
  • get more exercise by going for a daily walk or run

Read more about preventing constipation for more ways to change your diet and lifestyle.

Cautions of laxatives

Laxatives can cause side effects, which vary between the different types.

For example:

  • bulk-forming laxatives can cause bloating and flatulence (wind)
  • stimulant laxatives can cause abdominal (tummy) pain; using them for long periods of time can result in a weakened or 'lazy' bowel
  • osmotic laxatives can cause abdominal pain, bloating and flatulence
  • stool softener laxatives can cause abdominal cramps, a feeling like you are going to be sick (nausea) and a skin rash

Make sure you stay well hydrated when taking laxatives by drinking plenty of fluids. At least two litres (six to eight glasses) of water a day is recommended.

Less common side effects include:

  • being sick (vomiting)
  • dizziness - do not drive or use tools or machinery if you feel dizzy
  • passing blood out with your stools
  • fainting

If you experience any of these less common side effects then stop taking the laxatives and contact your doctor for advice.

Avoiding long-term use

In most cases, you should only take laxatives occasionally and on a short-term basis. Using laxatives frequently or every day can be harmful.

Using laxatives on a long-term basis can make your body dependent on them, so your bowel no longer functions properly without the medication.

Overusing laxatives can also cause:

If you need to use laxatives more regularly, or if you have been taking them for more than a week, see your doctor for advice.

Dosage of laxatives

All four main types of laxative – bulk-forming, stimulant, osmotic and stool softeners – are available without a prescription (over the counter) from pharmacies.

If self-help measures do not improve your constipation, taking laxatives for a short time may help. It is usually best to choose a bulk-forming laxative first, as it works in a similar way your bowels.

Always follow the dosage instructions on the patient information leaflet that comes with your medicine.

While taking a bulk-forming laxative, make sure you drink plenty of water (at least two litres, or six to eight glasses a day). As well as adding bulk to your stools, bulk-forming laxatives absorb water, so there is a risk you may become dehydrated.

If you are still constipated after taking a bulk-forming laxative, try an osmotic one. Osmotic laxatives help to soften faeces that are still hard after treatment with bulk-forming laxatives.

If bulk-forming laxatives and osmotic laxatives are not effective, try taking a stimulant laxative. See your doctor if you are still constipated after trying all of these types of laxative.

How often can I use laxatives?

Laxatives should only be used occasionally and for short periods of time. The patient information leaflet should recommend how often you take the medicine and state how long it usually takes to work. You can also ask your pharmacist for advice.

Never take more that the recommended dosage as taking too many laxatives in a short space of time can be dangerous and can lead to:

  • dehydration
  • cramping
  • dangerous changes to levels of minerals and salt inside your body

Some types of laxatives are designed to be taken at certain parts of the day such as first thing in the morning or last thing at night before sleeping. Check the patient information leaflet that comes with your medication.

You should stop taking a laxative as soon as your constipation improves. After taking a laxative, you can help prevent constipation returning by:

  • drinking at least two litres (six to eight glasses) of water a day
  • eating foods that are rich in fibre, such as fruit, vegetables and cereals
  • getting more exercise

These measures are a better way of preventing constipation than excessive use of laxatives.

See your doctor for advice if you are often constipated, despite taking the measures above, or if you have been taking laxatives for more than one week.

Do not get into the habit of taking over-the-counter laxatives every day to ease your constipation, because this can be harmful (see side effects of laxatives for more information).

In some cases, you may be prescribed a laxative to use regularly, but this should always be supervised by your doctor or a doctor who specialises in digestive conditions (gastroenterologist).

How to use laxatives

Most people can use laxatives, although not every type is suitable for everyon

Check with your doctor or pharmacist before using laxatives if:

  • you have a bowel condition, such as irritable bowel syndrome(IBS), Crohn’s disease or ulcerative colitis
  • you have a history of liver or kidney disease
  • you are pregnant or breastfeeding
  • you have an obstruction somewhere in your digestive system
  • you have diabetes – some laxatives can lead to a rise in blood sugar levels which could be dangerous for a person with diabetes
  • you have difficulties swallowing (dysphagia)
  • you have phenylketonuria, a rare genetic condition where the body cannot break down a substance called phenylalanine which is found in certain bulk-forming laxatives

In these cases, your doctor may recommend a particular type of laxative. For example, if you are pregnant and your constipation has not improved after eating more fibre and drinking more water, your doctor may recommend a bulk-forming laxative. If this does not work, they may recommend an osmotic laxative. As a last resort, they may prescribe a short course of a stimulant laxative.

Children and laxatives

Laxatives are not recommended for babies who have not yet been weaned. If they are constipated, try giving them extra water in between feeds. Gently massaging your baby's tummy and moving their legs in a cycling motion may also help reduce their constipation.

Babies who are eating solid foods and older children may be able to use laxatives. But you should first make sure your child drinks plenty of water or diluted fruit juice and increase the amount of fibre in their diet.

Read more about [treating constipation in children].

If after changing your child's diet they are still constipated, your doctor may prescribe or recommend a laxative. For children, osmotic or stimulant laxatives are likely to be prescribed before bulk-forming laxatives.

You should always check with your doctor before giving your baby or child a laxative.

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