Laxatives

Find out about different types of laxatives, including which to try first, how long they take to work and possible side effects.

What laxatives are for

Laxatives are a type of medicine that help you poo.

They're mainly used:

• to treat difficulty pooing (constipation)
• if you have a condition like an anal fissure, when it helps if your poo is soft or you can poo more easily
• if you have a condition or are taking a medicine that can cause difficulty pooing – you might be prescribed laxatives to make this less likely

They may also be used to make sure your bowels are empty before a scan or procedure, such as a colonoscopy.

For most adults with constipation, it's usually recommended you try lifestyle changes first, before using laxatives.

Find out how you can treat and prevent constipation yourself.

Types of laxative

There are 4 main types of laxative, which work in different ways.

How to use laxatives

Laxatives may come as:

• tablets, capsules or liquid you swallow
• liquid or packets of powder you mix with water and then drink
• medicine you put into your bottom where it dissolves (suppositories)
• liquids or gels you put inside your bottom (enemas)

Some laxatives may need to be taken at a certain time of day. The instruction leaflet that comes with your medicine will explain how and when to take it.

If you're taking bulk-forming or osmotic laxatives, it's important to drink plenty of fluids to avoid dehydration.

Side effects of laxatives

Like all medicines, laxatives can cause side effects.

Common side effects

Any side effects you may get depend on the type of laxative you're taking, but common side effects of most laxatives include:

• farting
• bloating
• stomach pain and cramps
• feeling sick (nausea) or being sick (vomiting)
• diarrhoea

These side effects are usually mild and should stop once you stop taking the laxative.

Serious side effects

If you use laxatives too often or for too long, they can cause problems such as:

• an allergic reaction (anaphylaxis) – causing symptoms such as a swollen throat or tongue, a raised and itchy rash, and difficulty breathing
• dehydration – causing symptoms such as headaches, feeling light-headed and pee that's darker than normal
• a blockage in your bowel (intestinal obstruction)
• low potassium in your blood – causing symptoms such as muscle weakness, tiredness, needing to pee a lot and heart rhythm problems

Who can take laxatives

Most adults can take laxatives.

Check with a pharmacist or doctor before taking laxatives if you:

• have ever had an allergic reaction to a laxative – this can include a skin rash, or swelling of the face and throat
• are pregnant or breastfeeding
• have a heart condition, such as heart failure
• have difficulty swallowing
• have a digestive a condition, like Crohn's disease or ulcerative colitis
• have a lactose intolerance – some laxatives contain lactose
• are taking opioid painkillers, such as codeine or morphine

You can usually still use laxatives, but some types might not be suitable for you. Always check the packet or leaflet that comes with the medicine.

Babies and children can take laxatives if recommended by a GP.

Constipation in children

Speak to a GP if you think your child is having difficulty pooing. Find out more about constipation in children.