Sounds like 'amox-i-cil-lin'

Amoxicillin is an antibiotic used to treat different infections caused by bacteria. Find out how to take it safely and possible side effects. Amoxicillin is also called Alphamox.

Type of medicine Also called
  • Antibiotic (to treat infections)
  • Penicillin antibiotic
  • Amoxil®
  • Alphamox®
  • Ospamox®

What is amoxicillin?

Amoxicillin is an antibiotic used to treat different infections caused by bacteria, such as chest infections, dental infections and infections of the throat, ear and sinus. It works by killing or stopping the growth of bacteria (bugs) and gets rid of the infection. Amoxicillin is sometimes used to get rid of Helicobacter pylori, an infection often found in people with stomach ulcers. It is not effective against infections caused by viruses. Amoxicillin belongs to a group of antibiotics called penicillins. In New Zealand amoxicillin is available as capsules and liquid and can be given as an injection in the hospital. 


  • The dose of amoxicillin will be different for different people depending on the type of infection and your age. 
  • Adults: the usual dose in adults is 250 or 500 milligrams 3 times a day.
  • Children: the dose for children will depend on their body weight. It is usually given 3 times a day.
  • Your doctor will advise you how long to take amoxicillin for (usually 3 to 7 days).
  • Always take your amoxicillin exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much to take, how often to take it and any special instructions.

How to take amoxicillin

  • You can take amoxicillin with or without food.
  • Capsules: swallow the capsules with a glass of water or milk. Do not chew them. 
  • Liquid: shake the medicine well. Measure the right amount using an oral syringe or medicine spoon. You can get these from your pharmacy. Do not use a kitchen spoon as it will not give you the right amount. Read more: Tips on how to give medicines to babies and children.
  • Timing: Amoxicillin is usually given 3 times a day. Try to space the doses evenly throughout the day, such as the first thing in the morning, early afternoon and at bedtime. Ideally these times should be at least 4 hours apart.  
  • Missed dose: If you forget to take your dose at the correct time, take one as soon as you remember. Try to take the correct number of doses each day, leaving at least 4 hours between doses. Do not take 2 doses at the same time to make up for a forgotten dose.
  • If you are sick: If you are sick (vomit) less than 30 minutes after having a dose of amoxicillin, take the same dose again. But, if you are sick (vomit) and it is more than 30 minutes after having a dose of amoxicillin, you do not need to take another dose. Wait until the next normal dose. 
  • Finish the course. It is best to take the whole course of antibiotics for the number of days your doctor has told you to. Do not stop taking it, even if you feel your infection has cleared up. 

Precautions when taking amoxicillin

Before starting amoxicillin

  • Do you have glandular fever?
  • Have ever had an allergic reaction to a medicine, especially a penicillin antibiotic?
    (Note, 9 out of 10 people who think they have a penicillin allergy do not – read more about penicillins and penicillin allergy)
  • Are you pregnant or breastfeeding?
  • Do you have problems with the way your kidneys work?
  • Are you taking any other medicines? This includes any medicines you are taking that you can buy without a prescription, as well as herbal and complementary medicines.

If so, it’s important that you tell your doctor or pharmacist before you start amoxicillin. Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care.

While taking amoxicillin

Store your capsules in a cool, dry place, away from direct heat and light. If you have been given liquid medicine, this will have been made up by the pharmacy and you may need to keep it in the fridge – check the instructions on the bottle. Make sure the medicine does not freeze.

What are the side effects of amoxicillin?

Like all medicines, amoxicillin can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Side effects What should I do?*
  • Nausea (feeling sick) or vomiting
  • Try taking amoxicllin with food.
  • If you have been vomiting and are taking the oral contraceptive pill, let your doctor or pharmacist know.
  • Diarrhoea (loose, watery stools)     
  • This may settle after a few days.
  • Tell your doctor if troublesome.
  • If you have diarrhoea and are also taking the oral contraceptive pill, let your doctor or pharmacist know.
  • Vaginal itching, soreness or discharge (thrush)
  • Tell your doctor or pharmacist.
  • Signs of an allergic reaction such as skin rash, itching, swelling of your lips, face and mouth, or difficulty breathing
  • Stop taking amoxicillin.
  • Tell your doctor immediately or phone HealthLine 0800 611 116.
*Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product


Amoxicillin may interact with some medicines and herbal supplements, so check with your doctor or pharmacist before starting amoxicillin. If you are taking the contraceptive pill, its effectiveness can be reduced if you have a bout of being sick (vomiting) or diarrhoea that lasts for more than 24 hours. If this happens, ask your doctor or pharmacist for advice about contraception over the following few days. 

Learn more

The following links have more information on amoxicillin.

New Zealand Formulary Patient Information:


  1. Amoxicillin New Zealand Formulary
  2. Antibiotics – choices for common infections BPAC, NZ, 2017
Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 26 Jun 2018