Get emergency medical help if you have any of these signs of an allergic reaction to erythromycin: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have a serious side effect such as:
- severe dizziness, fainting, fast or pounding heartbeats;
- diarrhea that is watery or bloody;
- hearing problems;
- vomiting or fussiness after eating (in a child taking erythromycin);
- nausea, upper stomach pain, itching, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or
- severe skin reaction -- fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.
Less serious erythromycin side effects may include:
- mild nausea, vomiting, diarrhea, or stomach pain;
- dizziness, headache, feeling tired;
- vaginal itching or discharge; or
- mild itching or skin rash.
This is not a complete list of side effects and others may occur.