Gaviscon (alginic acid)

1. About Gaviscon

Gaviscon can be used to treat heartburn (acid reflux) and indigestion.

The medicine works by forming a protective layer that floats on top of the contents of your stomach. This stops stomach acid escaping up into your food pipe. Gaviscon also contains an antacid that neutralises excess stomach acid and reduces pain and discomfort.

Gaviscon comes as chewable tablets, or a liquid that you drink (in bottles or in sachets). It also comes as a powder for babies and children under 2 years old.

You can buy Gaviscon from pharmacies and supermarkets. Some kinds of Gaviscon are available on prescription.


3. Key facts

  • You'll usually take Gaviscon after meals and at bedtime.
  • You should feel the benefit of taking Gaviscon soon after taking it, and it will last for around 4 hours.
  • It's safe to take paracetamol at the same time as Gaviscon but do not take ibuprofen or aspirin with it.
  • If you've bought Gaviscon without a prescription, do not take it for longer than 7 days without checking with a doctor.
  • There are different types of Gaviscon. Ask your doctor or pharmacist which one is best for you.

4. Who can and cannot take Gaviscon

Gaviscon can be taken by most adults and children aged 12 and over.

If your baby or child has problems with reflux or indigestion, talk to your doctor as soon as you can. Only treat them with Gaviscon if their doctor prescribes it.

To make sure this medicine is safe for you, tell your doctor or pharmacist if you have:

  • ever had an allergic reaction to Gaviscon or any other medicines
  • been advised to eat a low calcium or low salt (low sodium) diet
  • kidney or heart disease
  • a rare, inherited illness called phenylketonuria
  • low levels of phosphate in your blood

Children under 12

Never give Gaviscon to children under 12, unless their doctor prescribes it.

5. How and when to take Gaviscon

You'll usually take Gaviscon tablets and liquid up to 4 times a day. It's best to take it after meals and at bedtime. This is usually when the pain and discomfort is at its worst. But if your doctor has prescribed Gaviscon, take it when they tell you to.

Chew the tablets, do not swallow them whole. It's best to have a drink afterwards.

Mix Gaviscon powder (for babies and children under 2) with cool, boiled water or formula milk.


The dose depends on the type of Gaviscon you're taking. The liquid is usually one to two 5ml spoonfuls, up to 4 times a day. The tablets are usually 2 to 4 tablets, up to 4 times a day. Always check the packaging information.

Follow the instructions on the packaging or, if your doctor has prescribed it, take the dose they tell you to.

When to take Gaviscon

If you get occasional mild heartburn or indigestion, only take Gaviscon when you need it.

If you often have heartburn or indigestion, take Gaviscon regularly after meals and at bedtime, up to 4 times a day, whether or not you have symptoms.

If you've been taking Gaviscon for more than 7 days and you're still feeling uncomfortable or in pain, talk to your doctor.

What if I forget to take it?

If you usually take Gaviscon regularly but forget to take a dose, do not double your dose the next time. Just leave out the missed dose and take your next dose as normal.

If you forget doses often, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.

What if I take too much?

Taking too much Gaviscon may cause side effects such as wind and bloating (when your stomach feels tight and full of gas). This is unlikely to cause you any harm. If you are worried, talk to your doctor or pharmacist.

6. Side effects

Gaviscon is a very safe medicine. Most people who take it do not have any side effects. If you do get a side effect, it's likely to be mild and will go away when you stop taking Gaviscon.

Some types of Gaviscon may be more likely to make you feel sick or cause vomiting, constipation or diarrhoea because of their ingredients. Talk to your doctor or pharmacist if you notice any side effects that bother you or do not go away.

Serious allergic reaction

In very rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to Gaviscon. This happens in less than 1 in 10,000 people.

These are not all the side effects of Gaviscon. For a full list see the leaflet inside your medicines packet.


8. Pregnancy and breastfeeding

You can take Gaviscon while you're pregnant or breastfeeding.

However, if you have indigestion, it’s best to try and treat it without taking a medicine. For example, it can help to:

  • eat smaller meals more often
  • avoid fatty or spicy foods
  • raise the head of your bed a little

If this does not work, your doctor or midwife may recommend a medicine like Gaviscon.

9. Cautions with other medicines

Some medicines must not be taken at the same time as Gaviscon. This is because the medicines can affect how the other medicine works.

Do not take Gaviscon within 2 hours before or after taking:

Taking Gaviscon with painkillers

It's safe to take paracetamol at the same time as Gaviscon. But do not take other painkillers, like ibuprofen or aspirin, with Gaviscon without talking to your doctor or pharmacist first. These can make your symptoms worse.

Mixing Gaviscon with herbal remedies and supplements

There are no known problems with taking herbal remedies and supplements alongside Gaviscon.

10. Common questions about Gaviscon

Useful resources

Page last reviewed: 10/08/2021
Next review due: 10/08/2024