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What is psyllium husk used for?

Approved by our Clinical team | Feb 11, 2022

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Psyllium husk is a type of dietary fibre made from the seeds of a plant called plantago ovata. It’s sometimes called ispaghula husk – in fact, this name is more commonly used in the UK and Europe.

It is known as a “bulk-forming laxative” because it soaks up water in your digestive system and makes your stools softer and easier to pass. This makes it a good treatment for people who are regularly affected by constipation.

What is Fybogel?

Fybogel is a treatment made from psyllium husk that is readily available in UK pharmacies, with or without a prescription. It comes in sachets, sometimes flavoured with orange or lemon, and is mixed with cold water to be prepared as a drink.

Adults with constipation normally need to have two sachets of Fybogel a day after eating, once in the morning and once in the evening. You will normally take it in this way for up to seven days.

Who can use psyllium husk?

Products containing psyllium husk are perfectly safe for most people to take, which is why they’re available without a prescription.

However, before you take Fybogel or another treatment containing psyllium husk, you should tell your pharmacist or GP if you:

Have a bowel obstruction
Have muscle weakness of the bowel
Have phenylketonuria
Have ever had an allergic reaction to Fybogel or another medication

You should also speak to your doctor before taking Fybogel if you’re taking any of these prescription medications:

Carbamazepine (epilepsy and mood disorders)
Digoxin (heart conditions)
Mesalazine (gut problems)

Pregnancy and breastfeeding whilst taking psyllium husk

Psyllium husk is generally accepted to be safe when you’re pregnant or breastfeeding. This is good news for expectant mums, as constipation is a common symptom during pregnancy.

To make sure Fybogel is safe for you, tell your pharmacist or GP if you’re having any problems with your bowels (e.g. those listed above), if you’ve ever had an allergic reaction to similar products, or if you have phenylketonuria.

More guidance for pregnant and breastfeeding women on dealing with constipation can be found here.

Using psyllium husk

When to take psyllium husk

It’s recommended that you take Fybogel after eating – whether it’s a full meal or a snack.

Usually you’ll need to take it twice a day, once in the morning and once in the evening. When you take your evening dose you’ll need to make sure you wait an hour before you go to bed – if you go to sleep too soon, this can cause a blockage in the gut.

An easy habit to get into is to have Fybogel after you’ve eaten breakfast, and after you’ve eaten dinner.

How to take psyllium husk

The guidance for taking Fybogel involves a few simple steps:

Double check the Patient Information Leaflet for the product to make sure you’re taking the right amount in the right way – if in doubt, consult your pharmacist.
After eating in the morning or evening, open a sachet and tip the granules into a glass – avoid inhaling any of the powder when you do this as it can trigger an allergic reaction.
Measure out at least 150mls (or a quarter of a pint) of cold water and add it to the glass.
Stir well until the granules have dissolved – the solution will look clear or slightly cloudy.
Drink the full glass of Fybogel solution and – if you’re taking it in the evening – wait at least one hour before going to sleep.
Continue taking Fybogel in this way for as long as recommended by your GP or pharmacist.

While you’re taking Fybogel, it’s important to drink plenty of water throughout the day – ideally, six to eight glasses. If you don’t, your constipation could get worse.

Keeping on top of dosage

The standard Fybogel dosage for adults is one sachet twice a day – the dosage for children is different and should be checked with your pharmacist.

The general rule is to only take one dose (e.g. one sachet) at a time, even if you forgot to take your last one. When you do miss a dose, just take one as normal at the next scheduled time, rather than doubling up.

Taking more Fybogel than recommended shouldn’t do you any harm, but if you do accidentally take too much you should drink plenty of water and contact your GP for advice.

Most people who take Fybogel will start to feel better after two to three days. If your constipation hasn’t improved by this point, talk to your GP.

Side effects of using psyllium husk

The side effects associated with taking psyllium husk are minor, and won’t be experienced by everyone. Usually, people who do have side effects experience wind and bloating, simply because they’re having more fibre than usual.

Allergic reactions

It’s possible to have an allergic reaction to Fybogel, although this is more likely if you have other allergies and you’re preparing Fybogel frequently e.g. you’re a carer or healthcare worker.

A mild allergic reaction might cause itching in your eyes, nose or skin. A serious allergic reaction (anaphylaxis) is very rare and can cause skin rashes, trouble breathing and tightness in the chest or throat – if you experience these kinds of symptoms you should call 999 or go straight to A&E.