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Macrogols for constipation or bowel cleansing

CosmoCol, Movicol, Laxido

Carefully follow the printed information given with the preparation.

Mix the contents of the sachet into water before taking.

Common side-effects include feeling sick (nausea) and tummy (abdominal) discomfort or pain.

Continue reading below

About macrogols

Type of medicine

Osmotic laxative and bowel cleansing solution

Used for

Constipation; to evacuate the bowel before investigation or surgery

Also called

For constipation: CosmoCol®; Movicol®; Laxido®; Molaxole®; Strigol®
For bowel cleansing
: Klean-Prep®, Moviprep®

Available as

Sachets of powder or oral liquid medicine

Macrogols belong to a group of medicines known as osmotic laxatives. They are substances which are used medically to relieve constipation or to clear the bowel before some clinical procedures. They are sometimes called polyethylene glycols. Macrogols are identified by a number which represents their molecular weight so, for example, the macrogol used to relieve constipation is called macrogol '3350'.

Constipation is a common problem which can be caused by a number of things. Not eating enough fibre or not drinking enough fluid can cause constipation. Some conditions (such as pregnancy) can cause constipation, as can a lack of exercise or movement (such as being ill in bed) and some medicines. Macrogols relieve constipation by drawing water into your bowel to soften your stools, making them easier to pass.

Bowel cleansing solutions also contain macrogol '3350' although they are not treatments for constipation. They are used to ensure that the bowel is free of solid contents before a bowel examination or surgical procedure.

Before taking macrogols

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start the treatment it is important that your doctor or pharmacist knows:

  • If you are pregnant or breastfeeding.

  • If you have any bowel problems other than constipation, such as Crohn's disease, ulcerative colitis or toxic megacolon.

  • If you have a heart condition.

  • If you have ever had an allergic reaction to a medicine.

  • If you use starch-based food-thickeners to help with difficulty swallowing.

  • If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.

  • If the treatment is intended for a child. This is because laxatives should only be given to children on the advice of a doctor or healthcare professional.

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How to take macrogols

Before starting the treatment, read the manufacturer's printed information leaflet from inside the pack. It will tell you how to prepare your dose and how long the solution can be kept for after preparation. Once mixed with water, the solution should be kept in the fridge. Do not use any solution remaining after the time recommended in the manufacturer's instructions.

If taking for constipation (brands CosmoCol®, Movicol®, Laxido®, Molaxole®)

  • Your doctor will tell you how many sachets to take for each dose. A daily dose can range from 1-2 sachets daily, up to a maximum of 8 sachets daily. Unless the directions say otherwise, stir the contents of each sachet into half a glass of water (100-125 ml) before taking.

If taking for bowel cleansing (brands Klean-Prep®, Moviprep®)

  • You will be given written instructions from the clinic that will tell you how many sachets to make up into a solution, and when you should start to drink it. It is important that you follow the directions carefully.

  • You will also be given written instructions about what food or drink you can, or cannot, have until after the procedure is completed. Typically, the advice is to not eat any solid food from about two hours before you start drinking the solution. Again, it is important that you carefully follow the directions you are given.

  • The treatment can interfere with the absorption of medicines taken at the same time. If you take medication regularly, please ask your doctor about when to take your other medicines.

Getting the most from your treatment

If taking for constipation

  • A healthy diet containing fibre (wholegrain breads and cereals, bran, fruit and green leafy vegetables) with several glasses of water each day and daily exercise are important in maintaining healthy bowel function.

  • You can read more about how to prevent or treat constipation in the separate condition leaflets called Constipation (for adults) and Constipation in Children.

If taking for bowel cleansing

  • The preparation will start to work after an hour or two, so stay near to a toilet while you are taking the solution.

  • If you have any questions about the treatment, contact the hospital department where you are receiving the treatment for further advice.

Continue reading below

Can macrogols cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with macrogol '3350'. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.


macrogol '3350' side-effects

What can I do if I experience this?

Tummy (abdominal) pain, wind (flatulence), feeling sick (nausea)

These effects do not usually last for long. Drinking the solution more slowly may help

If you experience any other symptoms which you think may be due to the medicine, speak with your doctor or pharmacist for further advice.

How to store macrogols

  • Keep all medicines out of the reach and sight of children.

  • Store in a cool, dry place, away from direct heat and light.

Important information about all medicines

Important information about all medicines

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

If you are having an operation or any dental treatment, tell the person carrying out the treatment which medicines you are taking.

If you buy any medicines, check with a pharmacist that they are suitable to take with your other medicines.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine, ask your pharmacist.

Report side effects to a medicine or vaccine

If you experience side effects, you can report them online through the Yellow Card website.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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