Laxatives are a type of medicine that can help you empty your bowels if you are having trouble going to the toilet. They can be used to ease constipation and are available over the counter (without a prescription) from pharmacies and supermarkets.
Most people can use laxatives. Ideally, they 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.
How laxatives work
There are several types of laxative that work in different ways. The four main types are:
- 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 to retain fluid. This encourages your bowel to contract and move your faeces along. They take a few days to work and are taken by mouth as powders, granules or tablets.
- Stimulant laxatives speed up the movement of your bowel by stimulating the muscles that line your digestive tract. They usually take 6-12 hours to work, and come in many different forms, including tablets, liquids and suppositories or enemas (which are introduced through the anus).
- Osmotic laxatives make your stools softer by increasing the amount of water in your bowels. They usually take a few days to work and come in several different forms, including powders, liquids and enemas.
- Stool softener laxatives add water to your stools to lubricate them, making them more slippery and easier to pass. They are taken as capsules or enemas, and usually take one to two days to work.
Names of the different laxatives include:
- Fybogel, Celevac, Normacol (bulk-forming laxatives)
- Dulcolax, Normax, Senokot (stimulant laxatives)
- Movicol, Carbalax, Microlette (osmotic laxatives)
- Liquid paraffin or lactulose (stool softener laxatives)
Causes of constipation
Dehydration (lack of water in the body) and a low-fibre diet are the most common causes of constipation.
Before taking laxatives, try to ease your constipation naturally by drinking more water and eating more fibre (found in foods such as fruit, vegetables and cereals).
You may need to use laxatives if your constipation is caused by other factors, such as certain medications (e.g. codeine, antacids or antidepressants) or medical conditions (such as irritable bowel syndrome or underactive thyroid).
For a full list of factors that can make you constipated and need laxatives, go to Causes of constipation.
Who can use laxatives
Most people can use laxatives, although not every type is suitable for everyone. Check with your GP or pharmacist before using laxatives if:
- you have a bowel condition, such as irritable bowel syndrome (IBS) or ulcerative colitis (inflammation of the bowel)
- you have liver or kidney damage
- you are pregnant or breastfeeding
In these cases, your GP 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 GP 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 to reduce their constipation.
Babies who are eating solid foods and older children may be able to use laxatives. But you should first change their diet to include more fibre. . Also make sure that your child drinks plenty of water (without sugar added) or diluted fruit juice.
If after changing your child's diet they are still constipated, your GP may be able to 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 GP before giving your baby or child a laxative.
How to use laxatives
All four 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 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 GP 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.
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 GP for advice if you are often constipated, despite taking the measures above, or if you have been taking laxatives for more than two weeks.
Do not get into the habit of taking over-the-counter laxatives every day to ease your constipation, because this can be harmful.
In some cases, you may be prescribed a laxative to use regularly, but this should always be supervised by your GP.
Try natural methods first
Before using a laxative, try to ease your constipation by drinking more water, doing more exercise and having more fibre in your diet.
Fruit, vegetables and cereals that are high in fibre.
High fibre foods are important for good health. Eating more foods rich in fibre helps prevent constipation and to safeguard against other bowel problems.
Daily fibre guide:
- Having a high fibre cereal for breakfast each morning
- Try to use 100 per cent wholemeal bread
- Choose at least two vegetables each day
- Have one-two pieces of fruit each day
- Try to eat peas and beans regularly.
High fibre snacks:
- Baked beans on wholemeal toast
- Vegetable or lentil soup and wholemeal bread
- Mixed dried fruit and nuts
- Wholemeal scone and jam
- Stewed prunes and custard
- Breakfast cereals such as Bran Flakes or Weetabix and milk.
*All stewed fruit is a good source of fibre.
*Nuts are not a good form of fibre.
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, 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.
See your GP if you experience any severe side effects while taking a laxative.
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. Long term use should only be done under medical supervision.
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:
- unbalanced levels of salts and minerals in your body
If you need to use laxatives more regularly, or if you have been taking them for more than two weeks, see your GP for advice.