Gaviscon (alginic acid)


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

The medicine forms 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 tablets or liquid in bottles or 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.


  • It's usual to take Gaviscon after meals and at bedtime.
  • Do not give Gaviscon to a child under 12 years old, unless their doctor prescribes it.
  • It's safe to take paracetamol at the same time as Gaviscon but do not have 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.


Gaviscon can be taken by adults, including pregnant and breastfeeding women.

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.

Children under 12 years of age

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

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

  • had an allergic reaction to Gaviscon or any other medicines in the past
  • 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


It's usual to take Gaviscon 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 worst. If your doctor has prescribed Gaviscon, take it when they tell you to.

You can get Gaviscon as tablets. You can also get it as a liquid in bottles or sachets.

It comes as a powder for babies and children under 2 years old. You mix the powder with cool boiled water or formula milk.

How much to take

The dose depends on the type of Gaviscon you're taking.

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

When to take it

  • 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.

How long to take it for

Depending on the reason you're taking Gaviscon, you may only need it when you have symptoms. Or you may need to take it for a few weeks or months - or for many years.

Talk to your doctor about what is best for you.

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 by accident 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.


Gaviscon is a very safe medicine. Most people who take it don't 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 don't 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 patients.

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


Usually Gaviscon is safe to take during pregnancy and while breastfeeding.

If you're pregnant, it's best to try to treat indigestion 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 doesn't work, your doctor or midwife may recommend a medicine like Gaviscon.

Gaviscon and breastfeeding

Gaviscon is safe to take while you're breastfeeding. However, if your baby is premature or has health problems, check with your doctor first.


Some medicines must not be taken at the same time as Gaviscon. This is because the medicines can interfere with each other.

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

  • antihistamines
  • some antibiotics (quinolones and tetracyclines)
  • iron tablets
  • medicines to treat fungal infections
  • beta-blockers (for heart problems)
  • penicillamine (for rheumatoid arthritis)
  • steroids (for inflammatory and autoimmune disorders)
  • antipsychotic medicines (for mental health problems like bipolar disorder and schizophrenia)
  • chloroquine (for malaria)
  • estramustine (for prostate cancer)
  • bisphosphonates such as alendronic acid (to treat and prevent bone problems such as osteoporosis)
  • levothyroxine
  • a protein pump inhibitor (PPI) such as omeprazole and lansoprazole

It's safe to take paracetamol at the same time as Gaviscon. 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.


Page last reviewed: 17/08/2018
Next review due: 17/08/2021