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The Best Over the Counter Laxatives UK


Most over-the-counter laxatives in the UK are available without a prescription. There are four main classes of laxatives that patients can use to manage constipation effectively and fast.

Over-the-counter laxatives (UK) are licensed as General Sale List Products (GSL), available in any retail outlet including pharmacies, and Pharmacy Only medicines (P), which can only be purchased from registered pharmacies, including online pharmacies under a supervision of a pharmacist.

Within each class, over-the-counter laxatives have specific licensed age restrictions with some available for children only on prescription.

Always read the product information leaflet for detailed use or follow prescriber instructions on use and dosage.




What Causes Constipation (Video)?


Over The Counter Laxatives UK Classification

The most common laxatives belong to one of the following groups:

  1. Osmotic laxatives
  2. Bulk-forming laxative
  3. Stimulant (Irritant)
  4. Fecal softeners

The table below summarises the most common laxatives within each class, age restrictions, and availability. For more details, I encourage you to read the rest of this post.

Osmotic laxatives

Product Product availability Suitable from Onset of action Suitable in pregnancy
Lactulose Pharmacy-only Infants 1 day + Yes
Laxido Pharmacy-only 12+ 1 day + Yes
Movicol Pharmacy-only 12+ 1 day + Yes
CosmoCol Pharmacy-only 12+ 1 day + Yes
Molaxole Pharmacy-only 12+ 1 day + Yes*

Bulk-forming laxatives

Product Product availability Suitable from Onset of action Suitable in pregnancy
Fybogel GSL 6+ 1 day + Yes
Celevac GSL 12+ 1 day + No

Stimulant laxatives

Product Product availability Suitable from Onset of action Suitable in pregnancy
Senna tablets GSL 6+ 6-12 hours No
Senokot syrup GSL 2+ 6-12 hours No
Bisacodyl GSL 10+ ** 6-12 hours No
Dulcolax 10mg suppositories Pharmacy-only 10+ 10-30 minutes No
Dulcolax 5mg suppositories Pharmacy-only 4+ 10-30 minutes No
Glycerin suppositories GSL Infant + 10-30 minutes No ***

Fecal softeners

Product Product availability Suitable from Onset of action Suitable in pregnancy
Dioctyl capsules Pharmacy-only 12+ 1 day + No
Dulcoease capsules GSL 12+ 1 day + No
Docusate Adult oral solution Pharmacy-only 12+ 1 day + No
Docusate Paediatric oral solution Pharmacy-only 12+ 1 day + No

Pharmacy-only: Pharmacy-only medication, available in conventional or online pharmacies. Patients may need to ask a member of a pharmacy team to purchase pharmacy-only medication, as it may not be displayed in the pharmacy.

GSL: General Sale List medication can be sold in any retail outlet

* can only be used when recommended by a doctor

** Children between 4 and 10 years of age can use bisacodyl tablets only if recommended by a doctor.

*** A doctor may advise using suppositories in the pregnancy.

Which Laxative Works The Fastest?


Stimulant laxatives are the fastest in relieving symptoms of constipation.

When stimulant laxative is used in the form of suppositories (glycerin or bisacodyl suppositories), the onset of action (the time it takes to work) is between 10-30 minutes.

Bisacodyl or senna tablets can be taken at night to give relief in the morning.

Which Over-The-Counter Laxative To Choose First?

There is no set rule on which laxative to use first. In many cases changing a diet, particularly increasing fluid intake and increasing fiber (fruit and vegetables) in diet, can have the desired effect. An adult should aim to have around 30g of fiber per day (NICE, 2019).

If one produces a hard poo, an osmotic laxative may be a good option. If the poo is soft, a stimulant laxative may be preferred. Another option to consider is the likelihood of side effects (for example, stimulant laxatives are harsher on the stomach than osmotic or bulk-forming laxatives).

1.0 Osmotic Laxatives

Mechanism of action

Osmotic laxatives work by introducing more water in the bowel from the body, which in turn has a ‘softening’ effect on the stool, which is easier to pass.

How long does osmotic laxative take to work?

Osmotic laxatives generally take 1+ days to work. The exact times may vary between different osmotic laxatives and the initial dose taken. It may take 2-3 days for a full laxative effect to take place.

Osmotic laxatives: common side effects

Osmotic laxatives can cause side effects; however, frequency is not determined. Some side effects may include:

  • Gastrointestinal side effects such as diarrhea, vomiting, nausea, abdominal pain
  • Allergic reactions including skin reactions or even anaphylactic reactions are also possible

 Osmotic Laxatives: Most Common Osmotic Laxatives (UK)

In the UK two most commonly used osmotic laxatives are:

  • Lactulose
  • Macrogols contain products (such as macrogol 3350), for example, Movicol, CosmoCol, Laxido.

1.1 Lactulose


Lactulose is licensed as P medicine, available only from a pharmacy.

One cannot buy Lactulose over the counter.

Lactulose is a form of sugar, which is not absorbed when ingested.

Lactulose comes in the form of liquid, which tastes sweet.

Lactulose is a popular laxative choice as it is a ‘gentle’ type of laxative. Lactulose is licensed in infants under one year of age.

Can lactulose be used in pregnancy?

Lactulose can be used in pregnancy.

Lactulose: main side effects

A very common side effect associated with lactulose use is diarrhea. Common side effects include:

  • Nausea, vomiting
  • Abdominal pain (usually with higher doses)
  • Flatulence/wind (production of excessive gas), bloating. Flatulence often goes away after a few days of treatment.

How long does lactulose take to work?

It usually takes around 2-3 days before a full laxative effect is achieved. Some patients may experience the result within 24 hours of the first use. Stool frequency with lactulose use is dose-dependent.

Higher doses of lactulose increase stool frequency (Portalatin & Winstead, 2012).

Osmotic laxatives: macrogols

Macrogol produces a laxative effect through the osmotic effects. Macrogols containing osmotic laxatives are used to relieve constipation and additionally to help in resolving fecal impaction.

Macrogol laxatives are most commonly used in the form of a powder (sachets), which patients need to mix with water. Once mixed with water, the reconstituted solution should be refrigerated (2°C-8°C) and used within 6 hours.

Macrogols are also available as ready-made oral solutions.

Macrogol containing laxatives: age restrictions (adult vs. children range)

Macrogol laxatives are licensed as P medicines (available to buy from a pharmacy) to treat constipation in adults and children from 12 years of age.

Children’s range of macrogol laxatives can only be obtained on prescription with licensed use for children aged 2-11.

An adult version of macrogol laxatives usually contains 13.125g of macrogol 3350 per sachet, whereas the children version contains a half amount of macrogol 3350, 6.563 g per dose.

Osmotic laxatives containing macrogols:

1.2 Laxido


Laxido is available as an orange powder for making an oral solution (sachets) containing Macrogol 3350, 13.125g per sachet.

Laxido is licensed for adults and children from 12 years of age. Laxido is pharmacy-only medicine.

Can Laxido be used in pregnancy?

Laxido Orange can be used during pregnancy (eMC, 2019).

1.3 Movicol


The same age restrictions apply to Movicol products as with Laxido. In addition to the management of constipation, Movicol is also licensed for helping with fecal impaction.

For the management of chronic constipation.

prolonged use of Movicol lasting longer than two weeks in a row is not recommended.

Movicol contains 13.125g of macrogol 3350 per sachet.

Over the counter Movicol is available as:

  • Movicol (standard): lime and lemon flavour sachets
  • Movicol Chocolate sachets
  • Movicol Plain sachets
  • Movicol-Half sachets
  • Movicol Liquid

Can Movicol be used in pregnancy?

Movicol can be used during pregnancy (eMC, 2019).

1.4 CosmoCol range

CosmoCol range of macrogol containing osmotic laxatives include:


  • CosmoCol Orange Flavour oral powder sachets
  • CosmoCol Lemon and Lime Flavour oral powder sachets
  • CosmoCol Orange Lemon and Lime oral powder sachets
  • CosmoCol Plain oral powder sachet
  • CosmoCol Half oral powder 6.9g sachets

Can CosmoCol be used in the pregnancy?

CosmoCol should only be used in the pregnancy if treatment is considered essential by a doctor.

1.5 Molaxole


Less popular Molaxole is only licensed for adults and children over 12 years of age. It contains the same amount of macrogol 3350 as Laxido and Movicol. Lemon flavor Molaxole is licensed as a pharmacy-only medication for the management of constipation and fecal impaction.

Can Molaxole be used in pregnancy?

Molaxole should only be used in the pregnancy if treatment is considered essential by a doctor.

2.0 Bulk-Forming Laxatives Available Over The Counter UK

As the name suggests, bulk-forming laxatives add ‘bulk’ and increase fecal mass. Stools become softer and easier to pass. Bulk-forming laxatives are a gentle form of laxatives. Common over the counter bulk-forming laxatives include products containing dietary fiber, such as:

  • Ispaghula husk
  • Methylcellulose and
  • Sterculia

How long does it take for bulk-forming laxatives to work?

Bulk-forming laxatives usually take from 24 to 72 hours (full effect) to work.

Side effects associated with the use of bulk-forming laxatives:

Bulk-forming laxatives are generally well tolerated.

Some side effects related to their use include (frequency not known):

  • Flatulence (excess of wind)
  • Abdominal distention (enlargement of abdominal).
  • Bulk-forming can cause intestinal obstruction, oesophageal obstruction, fecal impaction (blockage of colon/rectum)

2.1 Bulk-forming laxatives: Fybogel (ispaghula husk)

Fybogel range of bulk-forming laxatives contains ispaghula husk as the main ingredient. Fybogel comes in the form of granules that are mixed with water. Mixed suspension should be ingested as soon as possible after mixing.

Fybogel is licensed for adults and children over 6 years of age. Fybogel can be purchased in any retail outlet (GSL license), and most pharmacies should stock it as well. Fybogel range includes:

  • Fybogel Orange Granules
  • Fybogel Plain Granules
  • Fybogel Hi-Fibre Lemon Granules
  • Fybogel Hi-Fibre Orange Granules

Important points to consider:

  • Fybogel (Ispaghula husk) should not be used by patients with suspected fecal impaction unless advised by a doctor.
  • Ispaghula husk should always be mixed with water.
  • Patients need to ensure adequate water intake to avoid potential obstruction of the throat (risk of choking) or esophagus (risk of intestinal obstruction).
  • Bulk-forming laxatives, including Fybogel, should not be used to relieve constipation caused by drugs, which reduces the movement of the gut, such as opioids, for example, codeine or co-codamol.
  • Fybogel (or any other bulk-forming laxative) should not be taken before going to bed.

Can you use Fybogel in pregnancy?

Fybogel can be used in pregnancy.

2.2 Bulk-forming laxatives: Methylcellulose

Methylcellulose is available in the form of tablets under the brand name Celevac. Each Celevac tablet contains 500 mg of methylcellulose. Celevac tablets have few licensed uses. Celevac tablets can be used in the management of simple constipation, and interestingly as an aid to appetite control and the treatment of obesity.

Although Celevac is licensed as a general sale product, most shops and even pharmacies do not stock it. Some pharmacies may stock Celevac as part of their dispensary stock, so one would need to ask the pharmacy team about the availability of this product. Alternatively, Celevac can be purchased online.

As with bulk-forming laxatives, patients are advised to drink plenty of water to avoid the possibility of fecal impaction or oesophageal obstruction due. When in contact with water, methylcellulose tablets absorb (take in) the water swell and create bulk in the stomach helping to restore regular bowel movements.

Can Celevac be used in the pregnancy?

The manufacturer of Celevac advises not to use Celevac (especially in the first trimester of the pregnancy) unless the benefit outweighs the risks to the fetus.

3.0 Stimulant Laxatives Available Over The Counter (UK)

Stimulant laxatives increase the movement of the intestines by stimulating colonic nerves, which start to contract and promote bowel movement. The most common stimulant laxatives (UK) in this category include senna tablets and bisacodyl tablets and suppositories.

How long does it take for stimulant laxatives to work?

Stimulant laxatives are usually taken at night before going to bed to produce the effect in the morning (time to effect: 6-12 hours).

Stimulant laxatives: side effects

Common side effects associated with stimulant laxative use include:

  • Gastrointestinal discomfort including pain, cramps
  • Diarrhea
  • Nausea

Can you use stimulant laxatives in pregnancy?

The use of senna is not recommended in the pregnancy. It is advised not to use bisacodyl in the pregnancy, especially in the first trimester. The use of bisacodyl in pregnancy should only be considered if the benefits outweigh the risks associated with the treatment.

Who cannot use stimulant laxatives?

Patient with specific conditions such:

  • Ileus (obstruction)
  • Intestinal obstruction
  • Stenosis (narrowing of a passage in the body)
  • Inflammatory colon diseases (Crohn’s disease, ulcerative colitis)
  • Severe dehydration
  • Electrolyte depletion
  • Should not use stimulant laxatives

For more details, refer to the patient information leaflet.

3.1 Stimulant laxatives: Senna

Senna can be purchased in any retail outlet, including pharmacies. Senna should only be used in the short term to treat constipation. Long-term use of a stimulant laxative may cause dysfunction of the intestine and dependence on this laxative for normal functioning.

Senna tablets are marketed under different brands, with the cheapest options being supermarket brands of senna tablets, including:

  • Tesco Senna Tablets (Senna Pods)
  • Boots Natural Senna Laxative
  • LloydsPharmacy Senna Tablets
  • Sainsbury’s Senna Tablets

Senokot is a common brand of senna tablets stocked by most supermarkets and pharmacies. There is not much difference between each product. Each product contains the same active ingredient, which is 7.5mg of Sennoside B.

What do Max strength senna products contain?

Each Max strength senna product, for example, Senokot Max Strength, contains 15mg of Sennoside B, per tablet instead of 7.5mg.

Senna drug interactions

Senna products can interact with some drugs (mainly some ‘heart’ drugs and some type of steroids), check product information leaflet for more details, or speak to a pharmacist.

Senna age restrictions

Senna tablets are licensed for adults and children who are 6 years of age or over. Senna is available in liquid form under the brand name Senokot 7.5 mg/5 ml Syrup.

Senokot syrup can be used in children from two years of age with recommended limited time for the use of 1-2 weeks.

The use of senna products for longer than one week requires medical supervision.

3.2 Stimulant laxatives: Bisacodyl

Similar to senna tablets, bisacodyl tablets can be purchased in most supermarkets and pharmacies. Bisacodyl Suppositories can only be purchased from the pharmacy.

Bisacodyl tablets are sold under many different brand names, including:

  • Asda Constipation Relief Tablets
  • Tesco Constipation Relief
  • Morrisons Laxative Tablets
  • Superdrug Constipation Relief Tablets
  • Sainsbury’s Constipation Relief
  • Boots Constipation Relief Tablets
  • Dulcolax

Bisacodyl: age restrictions

Bisacodyl tablets are licensed in adults and children from 10 years of age. Children between 4 and 10 years of age can use bisacodyl tablets only if recommended by a doctor.

Bisacodyl 10mg suppositories can be used by adults and children over 10 years of age, whereas bisacodyl 5mg suppositories by children over 4 years of age.

How long does it take for bisacodyl laxative to work?

Bisacodyl tablets are usually taken at night before going to bed, to give relief in the morning.
Bisacodyl suppositories take around 20 minutes to work; one would expect the laxative effect from 10-30 minutes after the insertion.

3.3 Stimulant laxatives: Sodium Picosulfate

Less commonly known sodium picosulfate is available as pharmacy medicine as a branded product called Dulcolax Pico Liquid.

Dulcolax Pico Liquid is licensed for adults and children over 10 years of age.
Children under 10 years of age, including toddlers, can use Dulcolax Pico Liquid only if recommended by a doctor.

3.4 Stimulant laxatives: Glycerin suppositories

Glycerin suppositories can be purchased from supermarkets or pharmacies. Pharmacies are more likely to keep all-size suppositories in stock. Glycerin suppositories come in three different sizes designed for three age groups:

  • Glycerin Suppositories 4g adult size
  • Glycerin Suppositories 2g children’s size
  • Glycerin Suppositories 1g infants’ size

How long does it take for glycerine suppositories to work?

Glycerin suppositories usually take between 15 to 60 minutes to work.

Can you use glycerine suppositories in the pregnancy?

Glycerin suppositories should be avoided during pregnancy. A doctor may advise to use suppositories in the pregnancy.

3.4 Glycerin suppositories possible side effects

Glycerin suppositories are well tolerated. Possible side effects may include:

  • Burning/irritation after the insertion
  • Abdominal pain
  • Cramps

4.0 Faecal Softeners Available Over The Counter (UK)

Fecal softeners increase the penetration of water and fats into the stool, making the stool softer and easier to pass. Docusate sodium is the main fecal softener available as:

  • Dulcoease and Dioctyl 100mg capsules
  • Docusate Sodium Paediatric 12.5mg/5ml Oral Solution
  • Docusate Sodium Adult 50mg/5ml Oral Solution

Docusate Sodium

Age restrictions

Docusate Sodium Paediatric is licensed for infants and children from 6 months of age up to 12 years of age. Docusate Paediatric can be mixed with fruit juice or milk.
Docusate capsules and an adult oral solution are licensed for adults and children from 12 years of age.

Docusate Sodium: side effects

Docusate Sodium is generally well tolerated. Abdominal cramps can be experienced by patients taking this medication.

Can you use docusate sodium in pregnancy?

The use of docusate sodium in pregnancy is only recommended if the benefits outweigh the potential risks of the treatment.

Over The Counter Laxatives UK: Conclusion

Customers have a wide choice of over-the-counter laxatives available in the UK. Many pharmacy-only laxatives may not be on display, customers may need to ask a member of staff to get a particular laxative. Patients who do not respond to laxative treatment or suffer from prolonged constipation should speak to their GP to get an appropriate assessment.

Quick FAQ

What is the best over the counter laxative?
No single laxative is the best. There is a number of over-the-counter laxatives. Stimulant laxatives work overnight. Stimulant suppositories within 10-30 minutes although harsher on the stomach. Other 'gentle' laxatives include bulk-forming and osmotic laxatives.
Can you get Dulcolax over the counter?
Ducolax can be purchased over the counter from a pharmacy or supermarket.
How can I instantly poop?
Stimulant suppositories work within 10-30 minutes from the insertion giving an almost instantaneous effect.
Do laxatives work if you have a blockage?
Some laxatives should not be used when the blockage is suspected. Osmotic laxatives containing macrogols can be used to treat faecal impaction (blockage).