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Alka-Seltzer XS (20)

  • Alka-Seltzer XS contains aspirin, paracetamol and caffeine.
  • Relieves headache, migraine, cold & flu symptoms, sore throat, fever, and aches & pains.
  • For adults and children over 16 years only.
  • Buy online from a licensed UK pharmacy.
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£5.79
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Fast & Free Delivery Options

Variety of delivery options including next day & free delivery.

100% UK-based Pharmacy

Pharmacy, clinic and prescribers based in Greater Manchester.

Free Online Consultations

Start your treatment with a quick and free online consultation.

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About Alka-Seltzer XS

Medication Name Alka-Seltzer XS
Type and Form of Medicine Effervescent tablets
What it Does Relieves headache, migraine, cold & flu symptoms, sore throat, fever, and aches & pains
Active Ingredients Aspirin, paracetamol, caffeine
Strength Each tablet contains aspirin 267mg, paracetamol 133mg, caffeine 40mg
Size 20 effervescent tablets
Patient Information Leaflet Click here

What is Alka-Seltzer XS?

Alka-Seltzer XS is an over-the-counter pain relief medicine combining aspirin, paracetamol and caffeine in an effervescent tablet. It provides short-term relief from headache, migraine, cold & flu symptoms, sore throat, fever, rheumatic and muscular pain, dental pain and period pain.

How does Alka-Seltzer XS work?

  • Aspirin: A non-steroidal anti-inflammatory drug (NSAID) that reduces pain, inflammation and fever.
  • Paracetamol: Provides pain relief and lowers fever.
  • Caffeine: A mild stimulant that enhances the pain-relieving effects.

The effervescent tablets dissolve in water for easier absorption.

Who is Alka-Seltzer XS suitable for?

Suitable for adults and children over 16 years.

Do not take if you:

  • Are allergic to aspirin, paracetamol, caffeine or other NSAIDs
  • Have stomach ulcers, bleeding disorders, or severe heart, kidney or liver disease
  • Are under 16 years old
  • Are pregnant or breastfeeding unless directed by a doctor

How to take Alka-Seltzer XS

  1. Dissolve 2 tablets in half a glass (about 100ml) of water before taking.
  2. Adults and children over 16: Take 2 tablets every 4 hours as needed.
  3. Do not take more than 8 tablets in 24 hours.
  4. Do not use for more than 3 days without medical advice.

Possible Side Effects

Like all medicines, Alka-Seltzer XS can cause side effects. Stop taking and seek help if you develop:

  • Allergic reactions such as rash, swelling or difficulty breathing
  • Stomach bleeding (vomit with blood, black stools)
  • Unexplained bruising or bleeding

Other effects may include indigestion, nausea or ringing in the ears. For a full list, see the patient information leaflet.

Ingredients

Active Ingredients: Aspirin 267mg, paracetamol 133mg, caffeine 40mg per tablet.
Other Ingredients: Citric acid, sodium bicarbonate, sodium carbonate, sodium benzoate (E211), sodium saccharin and other excipients.

Important Information

  • Not suitable for children under 16 years (risk of Reye’s syndrome).
  • Do not take with other medicines containing aspirin or paracetamol.
  • Contains sodium – ask your doctor if on a low-salt diet.
  • Avoid alcohol while taking this medicine.
  • Store out of the sight and reach of children.

Alka-Seltzer XS (20) Reviews

FAQs


Short-term relief of pain and fever, including headache, migraine, cold & flu symptoms, sore throat, muscular and rheumatic aches, dental pain and period pain.

Two tablets dissolved in half a glass (about 100 ml) of water every 4 hours if needed. Do not take more than 8 tablets in 24 hours.

No. Do not take with any other paracetamol-containing medicines.

No for children under 16 years. It is for adults and over-16s only.

Do not take unless your doctor advises you to.

Yes. Each tablet contains aspirin 267 mg and caffeine 40 mg (plus paracetamol 133 mg).

Speak to your doctor or pharmacist first. Alka-Seltzer XS contains sodium.

It’s for short-term use. Do not use for more than 3 days without medical advice.

Our Experienced UK-based Pharmacy Team

Clinical Consultant
MUDr, MRCEM, EBCEM, FRCEM
GMC no. 7176414

Pharmacist
MPharm
GPhC no. 2065469

Pharmacist
MPharm
GPhC no. 2046514

Page content authored by Muhammad, last reviewed by Amjad Khan on 15th September 2025.

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