What are the side effects of amoxycillin?

It is important to tell your health professional about any medicines you may be taking, or if you have any current illness or long-term health conditions. This will help them decide if amoxycillin is suitable for you.

If you have ever had an allergic reaction with symptoms such as hives, fever, breathing problems or anaphylactic shock when taking amoxycillin any other antibiotic in the past, you must tell your doctor.

Side effects of amoxycillin and other antibiotics from the penicillin family

(1 to 10 in 100 people)
(fewer than 1 in 100 people)
(fewer than 1 in 1000 people at high doses)
Rash (see below)
Thrush (candida infection)
Clostridium difficile infection
Nerve problems (e.g. drowsiness, hallucinations, coma, seizures)
Unusual bleeding
Low blood cell counts (neutropenia, thrombocytopenia)
Note: this is not a complete list of all the possible side effects of amoxycillin.


A red rash with bumps (maculopapular rash) covering large parts of the body is common with amoxycillin, especially if you take it for more than 7 days. The rash usually clears within a week of stopping amoxycillin. If you continue taking amoxycillin, the rash will take 6 to 14 days to clear. Check with your doctor if you develop a rash.

Allergic reactions to amoxycillin or other antibiotics from the penicillin family

Some people experience an allergic reaction to amoxycillin or other antibiotics from the penicillin family. This is due to an over-reaction of their immune system to the antibiotic.

Symptoms of an allergic reaction can include:

  • hives (large, red raised areas on the skin)
  • swollen lips, tongue or mouth
  • fever (a temperature of 38.5°C or higher)
  • breathing problems
  • fainting.

Seek medical advice if you experience any of these symptoms while you are taking amoxycillin.

It is not known why this happens to some people and not others, but it may mean that you will not be able to take amoxycillin and any penicillin-related antibiotic in the future. There are other types of antibiotics which don’t cause this reaction that will be suitable for you.

Read more about the common side effects of antibiotics.

Who can I ask about side effects?

If you’re concerned that you or someone in your care may have had side effects related to a medicine, seek medical advice. People with questions about their medicines or seeking general information about side effects can also call the NPS Medicines Line on 1300 633 424 (Monday-Friday, 9am-5pm AEST). To report possible side effects call the Adverse Medicine Events (AME) line on 1300 134 237 from anywhere in Australia (Monday–Friday, 9am–5pm AEST).

  • Rossi S, ed. Australian Medicines Handbook [online]. Adelaide: AMH, July 2012.
  • Sweetman S, ed. Martindale: The complete drug reference [online]. London: Pharmaceutical Press (accessed 18 October 2011).
  • Antibiotic Expert Group. Therapeutic Guidelines: Amoxycillin and ampicillin. Melbourne: Therapeutic Guidelines Limited, 2012 (accessed 27 March 2012).