Amoxicillin is a penicillin antibiotic used for bacterial infections — chest, ear, throat, sinus, dental and skin infections, and some urinary infections. It is one of the most prescribed medicines in South Africa. It has no effect on colds, flu or most sore throats, which are viral, and the course must be completed.

What is Amoxicillin?

Amoxicillin is a broad-spectrum antibiotic in the penicillin family. “Broad-spectrum” means it works against a fairly wide range of bacteria, which is why it is so often the first choice.

It attacks the bacterial cell wall. Bacteria need an intact wall to hold their shape and survive; amoxicillin blocks the enzymes that build and repair it, so the wall fails and the cell breaks apart. Human cells have no cell wall, which is why the medicine can destroy bacteria without damaging you — and why it does nothing whatsoever to viruses, which have no cell wall either.

You will see it spelled amoxycillin on much South African packaging. Same medicine, older spelling.

It is a Schedule 4 medicine, so prescription-only. It is dispensed as capsules, tablets, dispersible tablets and a suspension for children, and under many names: Betamox, Ultramox, Moxymax, Indo Amoxycillin, Austell Amoxicillin.

Some products add clavulanic acid — co-amoxiclav or Augmentin. Clavulanic acid blocks an enzyme some bacteria use to destroy amoxicillin, extending its range. That is a different product; check your pack.

What is Amoxicillin commonly used for?

Amoxicillin is prescribed for bacterial infections including:

Chest infections, including community-acquired pneumonia and some bronchitis.
Middle ear infections, particularly in children, where it is usually first-line.
Throat and tonsil infections caused by bacteria, most often streptococcus.
Sinus infections that are bacterial and not resolving.
Dental infections and abscesses, frequently with metronidazole to cover anaerobic bacteria.
Skin and soft tissue infections.
Some urinary tract infections, though resistance means other antibiotics are often preferred.
Helicobacter pylori eradication, combined with other antibiotics and an acid-reducing medicine.

Now the part that matters most, because it is the most common reason people take it unnecessarily. Amoxicillin does not treat colds, flu, or most sore throats and coughs. The overwhelming majority of those are viral. An antibiotic will not shorten a viral illness, will not prevent it becoming bacterial, and will not make you less infectious. What it will do is expose you to side effects and add to antibiotic resistance.

Most sore throats are viral. Most coughs are viral. Most sinus congestion is viral and settles on its own. A prescriber who does not give you an antibiotic for these is following the evidence, not withholding treatment.

How Amoxicillin fits into this medicine category

Amoxicillin is the most-used member of the penicillin class, and understanding what the classes cover explains why prescribers choose between them:

Class	Examples	Typically covers
Penicillins	Amoxicillin, flucloxacillin	Chest, ear, throat, dental, skin
Macrolides	Azithromycin, erythromycin	Chest and throat, some STIs; option in penicillin allergy
Quinolones	Ciprofloxacin	Urinary, some gut infections
Tetracyclines	Doxycycline	Chest, skin, some STIs
Nitroimidazoles	Metronidazole	Anaerobic and parasitic infections
Antifungals	Fluconazole, clotrimazole	Fungal infections only

That last row matters: no antibacterial treats a fungal infection. Thrush and athlete’s foot need an antifungal, and amoxicillin can actually make thrush more likely by disturbing normal bacterial balance.

The full group is on the antibiotics, antifungals and antimicrobials hub.

What to check before using Amoxicillin

Penicillin allergy is the first and most important check. If you have ever reacted to penicillin, amoxicillin or a related antibiotic, tell the prescriber and the pharmacist. Reactions range from a mild rash to anaphylaxis. Make sure it is recorded on your file.

Also tell them if:

You have glandular fever, or symptoms suggesting it. Amoxicillin very commonly causes a widespread rash in glandular fever, and is specifically avoided.
You have kidney disease.
You have had antibiotic-associated diarrhoea before, particularly C. difficile.
You are pregnant or breastfeeding. Amoxicillin is commonly used in both, but confirm.
You take warfarin, methotrexate or allopurinol.
The medicine is for a child — dosing is by weight and age, which is what the suspension is for.

Take the course exactly as prescribed, spacing doses evenly. Follow the dispensing label; this page does not set doses.

Possible cautions and when to ask a pharmacist or doctor

Finish the course. Feeling better after two or three days means the most susceptible bacteria are dead. The hardier ones are still there, and stopping hands them the field. That is the mechanism of antibiotic resistance, and it is not an abstraction — resistant infections are harder and sometimes impossible to treat.

Do not save leftovers or take someone else’s. A leftover course is the wrong drug, at the wrong amount, for the wrong duration.

Expect some digestive upset. Nausea and loose stools are common and usually mild. Severe or persistent diarrhoea, particularly with fever, abdominal pain or blood, needs medical attention — not an over-the-counter anti-diarrhoeal, which can make C. difficile worse.

Thrush is a common consequence, especially in women, because the antibiotic disturbs normal bacterial balance. A pharmacist can advise on an antifungal.

A rash needs assessment. Some are mild, some indicate true allergy, and a widespread rash may point to glandular fever.

Contraceptive pill — the interaction is smaller than once believed, but vomiting or diarrhoea can reduce absorption. Ask your pharmacist.

Seek urgent attention for swelling of the face, lips or tongue, difficulty breathing, a widespread or blistering rash, or severe diarrhoea. Return to the prescriber if symptoms worsen after two or three days.

Related medicine guides

Frequently asked questions

What is amoxicillin 500 mg used for? Bacterial infections — chest, ear, throat, sinus, dental and skin infections, and some urinary infections.

Will amoxicillin help a sore throat? Only if it is bacterial, which most are not. Your prescriber decides based on examination and sometimes a swab.

Will it help a cough or a cold? No. Those are viral. Antibiotics have no effect on them.

Is amoxicillin used for tooth infection? Yes, commonly — often with metronidazole to cover anaerobic bacteria. It is a holding measure; the dental problem still needs treating.

Why did I get thrush after taking it? Antibiotics disturb the normal balance of bacteria, which lets yeast overgrow. It is common and treatable — ask a pharmacist about an antifungal.

Can I stop when I feel better? No. Finish the course, or the more resistant bacteria are left behind.

What Is Amoxicillin Used For?