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ACIDEX Advance Aniseed Liquid - 500ml

ACIDEX Advance Aniseed Liquid - 500ml

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  • ✔️ Forms a protective alginate raft to block acid reflux
  • ✔️ Neutralises excess stomach acid for fast heartburn relief
  • ✔️ Dual-action formula targets both reflux and indigestion
  • ✔️ Pleasant aniseed flavour suitable for adults and over-12s
  • ✔️ 500ml bottle provides multiple doses for ongoing symptom control

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What Is ACIDEX Advance Aniseed Liquid and How Does It Relieve Heartburn?

 

If you've ever felt that uncomfortable burning sensation creeping up your chest after a meal, you'll know how disruptive heartburn can be. ACIDEX Advance Aniseed Liquid is an over-the-counter alginate antacid suspension designed to provide fast, effective relief from heartburn, acid reflux, and indigestion. Available in a 500ml bottle with a pleasant aniseed flavour, it's a practical choice for adults and children over 12 who need reliable symptom control. You can explore our full range of indigestion treatments if you're looking for additional options alongside this product.

Heartburn occurs when stomach acid flows back up into the oesophagus — a process known as gastro-oesophageal reflux. According to the NHS, it's a very common condition that affects people of all ages, often triggered by certain foods, lying down after eating, or being overweight. ACIDEX Advance Aniseed Liquid addresses this directly at the source, without requiring a prescription.

 

How Does ACIDEX Advance Aniseed Liquid Work?

 

The mechanism behind this product is elegantly straightforward. It contains three active ingredients that work together:

  • Sodium alginate — derived from seaweed, this forms a viscous gel when it contacts stomach acid, creating a physical "raft" that floats on top of stomach contents and acts as a barrier against reflux.
  • Sodium bicarbonate — reacts with stomach acid to produce carbon dioxide, which helps the alginate raft form quickly and also provides mild acid neutralisation.
  • Calcium carbonate — an antacid that directly neutralises excess gastric acid, reducing the acidity of any fluid that might still reach the oesophagus.

Together, these ingredients create a dual-action effect: physical barrier plus chemical neutralisation. The raft typically forms within a few minutes of taking the dose, which is why many people notice relief relatively quickly after swallowing.

 

Who Should Use ACIDEX Advance Aniseed Liquid?

 

This product is suitable for a broad range of people experiencing common digestive discomfort. It's particularly well-suited to those who prefer a liquid formulation over tablets — whether that's due to difficulty swallowing, personal preference, or simply finding liquids more convenient. That said, it isn't appropriate for everyone.

ACIDEX Advance Aniseed Liquid is generally suitable for:

  • Adults experiencing occasional heartburn or acid reflux after meals
  • Adults with symptoms of indigestion, including a feeling of fullness or discomfort
  • Children aged 12 and over (under medical supervision where appropriate)
  • Pregnant women experiencing heartburn — though always check with your GP or midwife first

It is not suitable for children under 12, and those on a sodium-restricted diet should use it with caution due to its sodium content.

 

How Does ACIDEX Advance Aniseed Liquid Compare to Other Antacid Liquids?

 

Feature ACIDEX Advance Aniseed Liquid Simple Antacid Liquid (e.g. calcium carbonate only)
Mechanism Alginate raft + acid neutralisation Acid neutralisation only
Reflux barrier Yes — physical raft formed No physical barrier
Suitable for reflux Yes Limited — targets acid only
Flavour Aniseed Varies by brand

 

Is ACIDEX Advance Aniseed Liquid Suitable for Long-Term Use and How Should It Be Stored?

 

This product is intended for short-term symptomatic relief. If you find yourself reaching for it daily for more than a week without improvement, that's a signal to speak to your GP — persistent symptoms could indicate an underlying condition that needs proper assessment. The NHS recommends seeking medical advice if heartburn occurs more than twice a week or doesn't respond to over-the-counter treatment.

Store ACIDEX Advance Aniseed Liquid below 25°C and do not freeze it. Keep the bottle tightly closed and out of reach of children. Once opened, check the label for any in-use expiry guidance. If you're managing other digestive concerns alongside heartburn, our IBS and cramps collection may also be worth exploring.

This product is a medicine. Speak to your doctor or pharmacist before using if you have an underlying medical condition or are taking other medicines.

ACIDEX Advance Aniseed Liquid 500ml specifications
Treatment category Heartburn, acid reflux, indigestion
Mechanism of action Alginate raft formation and antacid neutralisation
Effective for Heartburn, gastro-oesophageal reflux, indigestion
Suitable for Adults and children aged 12 and over
Active ingredients Sodium alginate, Sodium bicarbonate, Calcium carbonate
Pack size 500ml
UK classification General Sale List (GSL)
Drug class Alginate antacid
Preparation Oral suspension (liquid)
Route of administration Oral

Specifications of ACIDEX Advance Aniseed Liquid 500ml

 

What Is ACIDEX Advance Aniseed Liquid and What Is It Used For?

 

ACIDEX Advance Aniseed Liquid is an alginate-based antacid oral suspension used to relieve the symptoms of heartburn, acid reflux, and indigestion. It contains three active ingredients — sodium alginate (500mg/5ml), sodium bicarbonate (267mg/5ml), and calcium carbonate (160mg/5ml) — which work together to form a protective raft over stomach contents and neutralise excess acid. It is available without a prescription and is classified as a General Sale List (GSL) medicine in the UK.

The NHS describes heartburn as a burning feeling in the chest caused by stomach acid travelling up towards the throat. ACIDEX Advance Aniseed Liquid is specifically designed to address this by targeting the reflux mechanism itself, not just the acid. It is suitable for adults and young people aged 12 and over.

 

What Do You Need to Know Before Using ACIDEX Advance Aniseed Liquid?

 

Before taking this medicine, it's important to check whether it's appropriate for you. Do not use ACIDEX Advance Aniseed Liquid if any of the following apply:

  • You are under 12 years of age
  • You have been told to follow a low-sodium or sodium-restricted diet
  • You have phenylketonuria (if the product contains any relevant excipients — check the label)
  • You are allergic to any of the active or inactive ingredients
  • You have severe kidney disease (renal impairment) — seek medical advice first

You should also be aware of potential interactions with other medicines. Alginate antacids can affect the absorption of certain drugs if taken at the same time:

  • Antibiotics (e.g. tetracyclines, fluoroquinolones) — leave at least a 2-hour gap
  • Iron supplements — antacids can reduce iron absorption
  • Thyroid medicines (e.g. levothyroxine) — take at least 2 hours apart
  • Bisphosphonates (e.g. alendronic acid) — timing is critical; follow prescriber guidance
  • Some antifungals and HIV medicines — check with your pharmacist

Always tell your pharmacist about all medicines you are currently taking, including herbal remedies and supplements.

 

How Should You Use ACIDEX Advance Aniseed Liquid?

 

Always use this medicine exactly as described on the label or as directed by your pharmacist. Shake the bottle well before each use to ensure the suspension is evenly mixed.

  1. Shake the bottle thoroughly before opening.
  2. Measure the correct dose using the measuring cup or spoon provided.
  3. Take the dose after meals and at bedtime.
  4. Swallow the liquid directly — do not dilute with water.
  5. Do not take more than 4 doses in any 24-hour period.
Indication Age Group Dose Frequency
Heartburn / acid reflux Adults & children 12+ 10–20ml After meals and at bedtime (max 4 times daily)
Indigestion Adults & children 12+ 10–20ml After meals and at bedtime (max 4 times daily)
Children under 12 Under 12 Not recommended

 

What Are the Possible Side Effects of ACIDEX Advance Aniseed Liquid?

 

Like all medicines, ACIDEX Advance Aniseed Liquid can cause side effects, although not everyone experiences them. Most side effects are mild and resolve on their own. If you're also managing other digestive symptoms, our sickness and nausea range may offer complementary support.

Common side effects (may affect up to 1 in 10 people):

  • Bloating or a feeling of fullness
  • Flatulence (wind)
  • Mild nausea

Less common side effects (may affect up to 1 in 100 people):

  • Constipation or diarrhoea
  • Stomach cramps
  • Hypercalcaemia (raised calcium levels) with prolonged high-dose use — seek medical advice if you notice muscle weakness, confusion, or excessive thirst

Stop using this product and seek immediate medical attention if you experience signs of an allergic reaction, such as swelling of the face, lips, or throat, difficulty breathing, or a severe skin rash.

 

How Should You Store ACIDEX Advance Aniseed Liquid?

 

Correct storage helps maintain the product's effectiveness and safety. Follow these guidelines:

  • Store below 25°C in a cool, dry place
  • Do not freeze the liquid — freezing can alter the suspension
  • Keep the bottle tightly closed when not in use
  • Keep out of the sight and reach of children
  • Do not use after the expiry date printed on the label
  • Do not dispose of medicines via wastewater or household waste — return unused medicine to your pharmacist

If you're looking to support your overall digestive health alongside this product, you might find our vitamins and supplements collection useful for general gut wellness.

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Your safety and success are our highest priorities. Our medical team rigorously evaluates every product and piece of advice we provide, ensuring you receive only the most effective, science-backed solutions available.

Frequently Asked Questions

Where can I buy ACIDEX Advance Aniseed Liquid online in the UK?

You can buy ACIDEX Advance Aniseed Liquid 500ml directly from Cured Pharmacy, a GPhC-registered online pharmacy in the UK. It is available without a prescription as an over-the-counter medicine. Simply add it to your basket and choose your preferred delivery option at checkout.

How does ACIDEX Advance Aniseed Liquid work in the body?

When you swallow ACIDEX Advance Aniseed Liquid, the sodium alginate reacts with stomach acid to form a thick gel raft that floats on top of stomach contents. This raft acts as a physical barrier, preventing acid from refluxing back up into the oesophagus. The sodium bicarbonate and calcium carbonate components simultaneously neutralise excess stomach acid, providing dual-action relief.

How do I use ACIDEX Advance Aniseed Liquid step by step?

Using ACIDEX Advance Aniseed Liquid correctly is straightforward. Follow these steps:

  1. Shake the bottle well before each use.
  2. Measure 10–20ml using the measuring cup provided.
  3. Take the dose after meals and at bedtime.
  4. Do not exceed 4 doses in 24 hours.

Do not dilute the liquid with water, as this may reduce its effectiveness.

What is the correct dose of ACIDEX Advance Aniseed Liquid for adults?

The recommended adult dose is 10–20ml taken after meals and at bedtime, up to a maximum of four times daily. This means the maximum daily intake is 80ml. Always use the measuring cup provided to ensure accuracy, and do not exceed the stated dose.

When is the best time to take ACIDEX Advance Aniseed Liquid?

The most effective time to take ACIDEX Advance Aniseed Liquid is after meals and at bedtime. Taking it after eating allows the alginate raft to form on top of the stomach contents when acid production is at its highest. The bedtime dose is particularly helpful for people who experience night-time reflux or symptoms when lying down.

Can I take ACIDEX Advance Aniseed Liquid during pregnancy?

Alginate-based antacids are generally considered one of the safer options for managing heartburn during pregnancy, and the NHS acknowledges that antacids are commonly used in pregnancy. However, because this product contains sodium, you should always speak to your GP or midwife before taking it while pregnant. They can confirm whether it's appropriate for your individual circumstances.

Is ACIDEX Advance Aniseed Liquid suitable for children?

ACIDEX Advance Aniseed Liquid is suitable for young people aged 12 and over at the same dose as adults. It is not recommended for children under 12 years of age. If your child is under 12 and experiencing heartburn or reflux symptoms, speak to your GP for appropriate advice and treatment options.

What are the side effects of ACIDEX Advance Aniseed Liquid?

Side effects are uncommon but can include:

  • Bloating or flatulence
  • Mild nausea
  • Constipation or diarrhoea with prolonged use

If you experience any signs of an allergic reaction — such as swelling, difficulty breathing, or a severe rash — stop taking the product immediately and seek urgent medical attention.

How do I manage side effects of ACIDEX Advance Aniseed Liquid?

Most side effects, such as mild bloating or wind, are temporary and tend to resolve without any specific treatment. If you experience persistent nausea or digestive discomfort, try reducing your dose slightly and taking the liquid with a small amount of food. If side effects continue or concern you, speak to your pharmacist or GP for personalised guidance.

Can ACIDEX Advance Aniseed Liquid interact with other medicines?

Yes, alginate antacids can affect the absorption of certain medicines if taken at the same time. Leave at least a 2-hour gap between ACIDEX Advance Aniseed Liquid and:

  • Antibiotics (tetracyclines, fluoroquinolones)
  • Iron supplements
  • Levothyroxine (thyroid medicine)
  • Bisphosphonates (e.g. alendronic acid)

Always inform your pharmacist of all medicines you are taking before starting this product.

How long can I use ACIDEX Advance Aniseed Liquid for?

ACIDEX Advance Aniseed Liquid is designed for short-term symptomatic relief. If your symptoms persist for more than 7 days, worsen, or keep returning, you should consult your GP rather than continuing to self-treat. Persistent heartburn or reflux may indicate an underlying condition such as gastro-oesophageal reflux disease (GORD) that requires further investigation.

What happens if I miss a dose of ACIDEX Advance Aniseed Liquid?

If you miss a dose, simply take it as soon as you remember — unless it is nearly time for your next dose, in which case skip the missed one. Do not double up doses to make up for a missed one. ACIDEX Advance Aniseed Liquid is taken as needed for symptom relief, so missing an occasional dose is unlikely to cause any problems.

What are alternatives to ACIDEX Advance Aniseed Liquid?

Other alginate-based antacid liquids, such as Gaviscon Advance, work in a similar way and may be suitable alternatives. Simple antacid liquids containing only calcium carbonate or magnesium hydroxide are also available but do not provide the same physical raft barrier. You can browse our full indigestion treatments collection to compare available options.

Is ACIDEX Advance Aniseed Liquid suitable for people on a low-sodium diet?

This product contains sodium, so it may not be suitable if you have been advised to follow a low-sodium or sodium-restricted diet — for example, if you have high blood pressure, heart failure, or kidney disease. Speak to your GP or pharmacist before using it if sodium intake is a concern for you. They may be able to suggest a lower-sodium alternative.

What are the latest findings on alginate antacids for heartburn relief?

Alginate-based antacids have been well-studied and are recognised by the NHS and NICE as an effective first-line option for managing heartburn and mild gastro-oesophageal reflux. Clinical evidence supports their use as a physical barrier against acid reflux, with a good safety profile for short-term use. If you're also experiencing related digestive issues, our IBS and cramps range may offer further support.

How Should You Use ACIDEX Advance Aniseed Liquid?

Before taking your dose, shake the bottle thoroughly to ensure the suspension is evenly mixed — the active ingredients can settle at the bottom between uses. Always use the measuring cup or spoon provided with the product to get an accurate dose, and take the liquid directly without diluting it with water.

What Is the Correct Dose of ACIDEX Advance Aniseed Liquid?

The dose varies depending on the severity of your symptoms, but you should never exceed the maximum daily amount. Always start with the lower end of the dose range and increase only if needed.

When Is the Best Time to Use ACIDEX Advance Aniseed Liquid?

Timing matters with alginate antacids. Taking ACIDEX Advance Aniseed Liquid after meals — rather than before — allows the alginate to interact with the stomach contents and form an effective raft on top of the food and acid mixture. The bedtime dose is particularly valuable for people who experience symptoms when lying down or during the night, as it helps maintain the protective barrier while you sleep.

If you are taking other medicines, leave at least a 2-hour gap between those medicines and your dose of ACIDEX Advance Aniseed Liquid to avoid any interaction affecting absorption.

How Long Can You Use ACIDEX Advance Aniseed Liquid For?

This product is intended for short-term use to relieve occasional heartburn, acid reflux, and indigestion. If your symptoms have not improved after 7 days of regular use, or if they are getting worse, you should stop using the product and speak to your GP. Frequent or persistent heartburn can sometimes indicate an underlying condition such as gastro-oesophageal reflux disease (GORD), which may require a different treatment approach.

Do not use this product continuously for extended periods without medical advice, particularly if you are on a sodium-restricted diet, as the sodium content may be a consideration over time.

Do not exceed the recommended dose. If in doubt, speak to your pharmacist.

Customer Reviews

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A
Anonymous

Good, and cheaper than Gaviscon but just as effective.

G
Gavin
**Amazing Relief for Acid Reflux and Heartburn!**

I’ve struggled with acid reflux and heartburn for years, and this liquid medication has been an absolute lifesaver! It works fast—within minutes of taking it, I feel the burning sensation ease, and it provides lasting relief. Unlike other medications I’ve tried, the liquid formula is so easy to take, and it coats my throat, giving me extra protection against acid. The taste is pleasant too, which is a big plus. I also love that I can rely on this whenever I have a flare-up, especially after a big meal or at night. Highly recommend this to anyone looking for quick and effective relief!

What Are the Most Common Side Effects of ACIDEX Advance Aniseed Liquid?

Most people tolerate ACIDEX Advance Aniseed Liquid well, and side effects are generally uncommon. When they do occur, they tend to be mild and short-lived. The most frequently reported effects relate to the digestive system, which makes sense given that this is an oral antacid suspension.

  • Bloating or a sensation of fullness in the stomach
  • Flatulence (wind)
  • Mild nausea shortly after taking the dose

What Are the Less Common Side Effects of ACIDEX Advance Aniseed Liquid?

Less commonly, some people may experience changes in bowel habit or other digestive symptoms, particularly with prolonged or high-dose use. These are not typical with short-term use at the recommended dose.

  • Constipation
  • Diarrhoea
  • Stomach cramps or abdominal discomfort
  • Hypercalcaemia (raised blood calcium levels) — only a risk with prolonged high-dose use; symptoms include muscle weakness, confusion, excessive thirst, or frequent urination

What Are the Serious Side Effects of ACIDEX Advance Aniseed Liquid?

Serious side effects are rare but require immediate attention. Stop taking ACIDEX Advance Aniseed Liquid and seek urgent medical help if you notice any of the following signs of a severe allergic reaction (anaphylaxis):

  • Swelling of the face, lips, tongue, or throat
  • Difficulty breathing or swallowing
  • Severe skin rash, hives, or itching
  • Sudden dizziness or feeling faint

These reactions are very uncommon, but they are a medical emergency. Call 999 or go to your nearest A&E immediately if you experience them.

What Should You Do If You Experience Side Effects of ACIDEX Advance Aniseed Liquid?

For mild side effects such as bloating or wind, these often resolve on their own without any specific treatment. You can try taking a slightly lower dose to see if this reduces the discomfort. If nausea is a problem, ensure you are taking the liquid after food rather than on an empty stomach. Always report any side effects that concern you to your pharmacist or GP, who can advise on whether to continue, adjust, or stop the treatment.

You can also report suspected side effects directly to the MHRA via the Yellow Card scheme at yellowcard.mhra.gov.uk.

Can ACIDEX Advance Aniseed Liquid Interact With Other Medicines?

Yes. Because ACIDEX Advance Aniseed Liquid contains antacid components, it can interfere with the absorption of certain other medicines if taken at the same time. This doesn't mean you can't take other medicines — it simply means timing is important. Leave at least a 2-hour gap between this product and medicines such as antibiotics (particularly tetracyclines and fluoroquinolones), iron supplements, levothyroxine, and bisphosphonates like alendronic acid. Always inform your pharmacist of everything you are currently taking before starting this product.

If you are concerned about any side effects, contact your pharmacist or GP immediately.

Patient Information Leaflet

Important - Before taking any medication, it is always important to read the Patient Information Leaflet (PIL)

Written and reviewed by our qualified team

GPhC Number: 2233073
Tarun Kumar

Reviewed by:

Tarun Kumar

Superintendent/ Clinical Lead

📖 Find out more about our team of medical content authors and how we ensure the accuracy of our content with our content guidelines.

Content last updated: 31 Mar 2025

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