Like all medicines, amoxicillin can cause side effects in some people, but many people have no side effects or only minor ones.
Common side effects of amoxicillin
These common side effects of amoxicillin can happen in up to 1 in 10 people who take the medicine. There are things you can do to help cope with them:
Skin rash
If you get a skin rash, it may help to take an antihistamine which you can buy from a pharmacy. Check with the pharmacist to see what type is suitable for you.
Feeling sick (nausea)
Stick to simple meals and do not eat rich or spicy food. It might help to take your amoxicillin after a meal or snack
Diarrhoea
Drink plenty of fluids, such as water or squash, to avoid dehydration. Signs of dehydration include peeing less than usual or having dark, strong-smelling pee.
Do not take any other medicines to treat diarrhoea without speaking to a pharmacist or doctor.
If you take the combined contraceptive pill or progestogen-only pill and you have severe, watery diarrhoea, or any diarrhoea that lasts for more than 24 hours, your contraceptive pills may not protect you from pregnancy. Check the pill packet to find out what to do.
Speak to a doctor or pharmacist if the advice on how to cope does not help and a side effect is still bothering you or does not go away.
Serious side effects
Serious side effects are rare by may occasionally happen.
Stop taking amoxicillin capsules and call a doctor or call 111 now if you get:
- diarrhoea (possibly with stomach cramps) that contains blood or mucus or severe diarrhoea
- pale poo and dark pee, and the whites of your eyes or your skin turn yellow (although this may be less obvious on brown or black skin) – these can be signs of liver or gallbladder problems
- bruising more than usual or changes in your skin colour
- joint or muscle pain that starts after about 2 days of taking the medicine
- a skin rash with circular red patches (this may be less obvious on brown or black skin) and a high temperature
Some of these serious side effects can happen up to 2 months after finishing the amoxicillin.
Delayed allergic reactions can happen around 7 to 12 days after taking amoxicillin capsules. The allergic reaction is usually a mild skin rash, but you may also have a high temperature, joint pain and swollen glands, particularly in the armpit.
Around 1 in 10 people have an allergic reaction to amoxicillin.
Serious allergic reaction
In rare cases, amoxicillin can cause a serious allergic reaction (anaphylaxis).
Immediate action required: Call 999 now if:
- your lips, mouth, throat or tongue suddenly become swollen
- you're breathing very fast or struggling to breathe (you may become very wheezy or feel like you're choking or gasping for air)
- your throat feels tight or you're struggling to swallow
- your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
- you suddenly become very confused, drowsy or dizzy
- someone faints and cannot be woken up
- a child is limp, floppy or not responding like they normally do (their head may fall to the side, backwards or forwards, or they may find it difficult to lift their head or focus on your face)
You or the person who's unwell may also have a rash that's swollen, raised, itchy, blistered or peeling.
These can be signs of a serious allergic reaction and may need immediate treatment in hospital.
Do not drive yourself to A&E.
The person you speak to at 999 will give you advice about what to do.
Other side effects
These are not all the side effects of amoxicillin. For a full list see the leaflet inside your medicines packet.
Reporting side effects
You can report any suspected side effect using the Yellow Card safety scheme.
Visit the Yellow Card website for more information about reporting side effects.