Gaviscon treats heartburn and acid reflux, and it works differently from an antacid. Rather than only neutralising acid, it forms a floating gel raft on top of the stomach contents that physically blocks reflux into the oesophagus. It is one of the few reflux treatments considered suitable in pregnancy.
What is Gaviscon?
Gaviscon products are alginate preparations. The South African Medicine Price Registry lists:
| Product | Schedule | Form | Contains |
|---|---|---|---|
| Infant Gaviscon Aluminium Free | S4 | Powder | Sodium alginate 225 mg, magnesium alginate |
Adult Gaviscon liquids and tablets are widely sold as general-sale or pharmacy products and typically combine an alginate with antacid salts — commonly sodium bicarbonate and calcium carbonate. Read your own pack, since formulations differ between products and countries.
The mechanism is genuinely different from ordinary antacids, and it is worth understanding:
Alginates come from seaweed. On contact with stomach acid, the alginate precipitates into a gel and the bicarbonate reacts with acid to release carbon dioxide. That gas is trapped in the gel, making it buoyant, and it floats to the top of the stomach contents as a raft.
Reflux happens when stomach contents move up into the oesophagus. The raft sits at exactly the point where that would begin, so what refluxes first is the neutral gel rather than acid.
Two consequences:
It is particularly good for reflux specifically — the burning behind the breastbone, acid coming up into the throat, the symptoms that are worse lying down or bending over.
It works quickly and briefly, typically within minutes and lasting a few hours. It is a symptomatic treatment, not one that reduces acid production.
Infant Gaviscon is a different product with different rules. It is Schedule 4 here, is prescribed for reflux in babies, and is mixed into feeds. Do not give adult Gaviscon to an infant, and do not use the infant product without medical direction — reflux in babies is usually normal and self-resolving, and treatment is not always the right answer.
What is Gaviscon commonly used for?
- Heartburn — the burning behind the breastbone.
- Acid reflux and regurgitation, including the sour taste at the back of the throat.
- Reflux at night or when lying flat, where the raft mechanism is most useful.
- Reflux in pregnancy. This is an important use — heartburn affects a large proportion of pregnancies, and alginates are among the first treatments recommended because they act locally and are minimally absorbed.
- Indigestion after meals.
- Reflux-related throat symptoms, including a persistent cough, hoarseness or the sensation of a lump in the throat.
- Reflux in infants, using the infant formulation on medical advice.
It is for occasional or short-term use in adults. If you need it most days, that is a signal rather than a routine — persistent reflux usually responds better to a medicine that reduces acid production, such as omeprazole, and it also deserves a look at why it is happening.
Practical measures matter alongside: eating smaller meals, not lying down within three hours of eating, raising the head of the bed, losing excess weight, and reducing alcohol, smoking and late-night eating. These are unglamorous and they work.
How Gaviscon fits into this medicine category
| Group | Examples | Speed and duration |
|---|---|---|
| Alginates | Gaviscon | Minutes; a few hours; physically blocks reflux |
| Antacids | Eno, aluminium and magnesium salts | Minutes; short-lived; neutralise only |
| H2 blockers | Famotidine, cimetidine | About an hour; several hours |
| Proton pump inhibitors | Omeprazole, lansoprazole | Days to full effect; strongest and longest |
| Antispasmodics | Hyoscine (Hyospasmol) | Cramping, not acid |
| Prokinetics | Metoclopramide (Adco-Contromet) | Nausea and stomach emptying |
A common and sensible combination is a proton pump inhibitor daily for control, with an alginate kept for breakthrough symptoms. See the digestive and stomach medicines hub.
What to check before using Gaviscon
Check the sodium content, particularly with liquid formulations, which can carry a significant sodium load.
Speak to a pharmacist or doctor if you:
- Have high blood pressure, heart failure, kidney disease or liver disease, or are on a low-salt diet.
- Have high blood calcium, kidney stones, or take calcium supplements — relevant to calcium-containing formulations.
- Are pregnant. Alginates are generally regarded as suitable, but confirm which product.
- Are treating an infant. Use only the infant product, on medical advice.
- Take other medicines. Alginates and antacids reduce the absorption of a long list of them — including some antibiotics, iron, thyroid medicine and HIV medicines such as dolutegravir. Separate them by about two hours in either direction.
Practical points:
- Take it after meals and at bedtime, which is when reflux occurs. This is the opposite of a proton pump inhibitor, which goes before breakfast.
- Do not lie down immediately after taking it — the raft needs to form.
- Shake liquids well, and chew chewable tablets thoroughly.
- Do not exceed the daily maximum, and do not use it continuously for more than a couple of weeks without advice.
Possible cautions and when to ask a pharmacist or doctor
Gaviscon is very well tolerated. Occasional effects include bloating, wind, nausea and constipation or loose stools, depending on the salts in the formulation.
Get emergency help for:
- Chest pain, pressure or tightness, particularly with breathlessness, sweating, nausea, or pain spreading to the arm, neck or jaw. Heart attack pain is frequently mistaken for heartburn, and reflux remedies are frequently taken instead of calling for help. If in any doubt, treat it as cardiac.
- Vomiting blood, or material like coffee grounds.
- Black, tarry stools.
- Severe abdominal pain.
- Swelling of the face, lips or tongue, or difficulty breathing.
See a doctor if:
- You need it most days, or for more than two weeks.
- Heartburn wakes you at night, or comes with a persistent cough or hoarseness.
- You have difficulty or pain swallowing, or food sticking.
- There is unintentional weight loss, persistent vomiting, or loss of appetite.
- You are over 45 with new indigestion.
- An infant is vomiting forcefully, not gaining weight, refusing feeds, has blood in the vomit or stool, or seems unwell — reflux in babies is usually harmless, but those signs are not.
Related medicine guides
Frequently asked questions
What is Gaviscon used for? Heartburn, acid reflux and regurgitation. It forms a floating gel raft on the stomach contents that physically blocks reflux into the oesophagus.
How is it different from an antacid? An antacid neutralises acid. Gaviscon also forms a barrier that stops stomach contents refluxing upwards, which makes it particularly useful for reflux rather than general indigestion.
How quickly does it work? Within minutes, lasting a few hours.
When should I take it? After meals and at bedtime — when reflux happens. Do not lie down immediately afterwards.
Can I use it in pregnancy? Alginates are among the first treatments recommended for heartburn in pregnancy. Check with a pharmacist which product is suitable.
Can I give it to my baby? Only the infant formulation, on medical advice. Adult products are not suitable for infants.
Can I take it with my other medicines? Separate them by about two hours. Alginates and antacids reduce absorption of many medicines.
Can I use it every day? Not long-term without advice. Daily heartburn usually needs an acid-reducing medicine and a doctor’s assessment.