How does macrogol work?
Macrogol is a type of laxative called an osmotic laxative. This means it draws water from the rest of the body into your bowel to make your poo slightly bigger and softer.
It then triggers your bowels to start working to push the poo out.
When will I feel better?
Macrogol can take 1 to 2 days to start working.
Talk to a doctor if you are still constipated after 3 days.
Are there any long-term side effects?
Ideally, you'll only take macrogol occasionally and for a few days at a time.
Using laxatives like macrogol for longer can lead to diarrhoea that lasts a long time, and can cause an electrolyte imbalance. This is where levels of substances like sodium, potassium and magnesium in your body get too high or too low.
In some people, a severe electrolyte imbalance can cause serious health problems such as:
- muscle spasms
- twitching
- a seizure or fit
However, sometimes a doctor may recommend you or your child take macrogol for a few months. This could be because you keep getting constipation or you take medicines that make you constipated. Your doctor will advise you how long you need to take macrogol for and how much to take.
How does macrogol compare with other laxatives?
There are other types of laxatives. Some work in a different way to macrogol but are equally good at treating constipation. Some work more quickly than macrogol.
Bulk-forming laxatives, such as Fybogel and methylcellulose, increase the "bulk" or weight of poo which in turn stimulates bowel movement. They take 2 or 3 days to work. They are normally tried first before trying a laxative like macrogol.
Stimulant laxatives, such as senna and bisacodyl, speed up your bowels by stimulating the nerves that control the muscles lining your gut. They work more quickly than other laxatives. If you take them at bedtime, they work overnight. They are normally tried after a laxative like macrogol has not worked.
Surface-wetting laxatives, such as arachis oil and docusate, let water get into poo to soften it and make it easier to pass.
Will it affect my contraception?
Macrogol does not affect any type of contraception including the combined pill, progestogen-only pill or emergency contraception.
But if macrogol makes you sick (vomit) or have severe diarrhoea for more than 24 hours, your contraceptive pills may not protect you from pregnancy. Look on the pill packet to find out what to do.
Find out more:
Can I drive or ride a bike?
Yes, macrogol has no effect on driving, riding a bike or using machinery.
Can I drink alcohol while taking macrogol?
Yes, you can drink alcohol with macrogol.
Is there any food and drink I need to avoid?
You can eat and drink normally while taking macrogol.
It might help to cut down on foods such as pastries, puddings, sweets, cheese and cake, as these foods can make constipation worse.
To help with constipation, eat more fibre, such as fresh fruit, vegetables and cereals, and drink plenty of water.
Can lifestyle changes help constipation?
It's often possible to improve constipation without having to use laxatives.
Before trying macrogol, or to stop constipation coming back, it may help to:
- get more fibre into your diet – aim for about 30g of fibre a day. High-fibre foods include fruit, vegetables and cereals. If you're not used to a high-fibre diet, increase the amount of fibre you eat gradually
- add bulking agents, such as wheat bran, oats or linseed, to your diet – these will help make your poo softer and easier to pass (although bran and fibre can sometimes make bloating worse)
- drink plenty of water – to keep poo soft
- exercise regularly – keeping your body active will help to keep your gut moving