Erythromycin
Tablet or syrup
Quick Summary
Erythromycin is one of the older macrolide antibiotics.
Medical Uses
How it's taken
Take it as prescribed.
Take it for the full course, even if you feel better, unless your doctor tells you otherwise. Don't share antibiotics or keep leftovers.
Your doctor decides the right dose for you and how long to take it.
Your doctor decides the right dose for you. Follow their instructions and the label.
Common Side Effects
Nausea
And tummy cramps.
Diarrhoea
Common.
Rash
Sometimes.
Interactions
Statins and other medicines
Many interactions; check with your doctor.
Critical Warnings
Heart rhythm
Can affect heart rhythm.
Severe or bloody diarrhoea
Can be a sign of a serious bowel infection. Contact a doctor.
Severe allergic reaction
Black Box Warning: Swelling of the face or throat, difficulty breathing or a widespread rash: get emergency help.
Antibiotic resistance
Using antibiotics when they aren't needed makes them less effective for everyone.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Erythromycin: drug information(opens in a new tab) · MedlinePlus, US National Library of Medicine
- Erythromycin: antibiotic for bacterial infections(opens in a new tab) · NHS