Get emergency medical help if you have signs of an allergic reaction to erythromycin (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).
Call your doctor at once if you have:
severe stomach pain, diarrhea that is watery or bloody (even if it occurs months after your last dose);
headache with chest pain and severe dizziness, fainting, fast or pounding heartbeats;
a seizure;
hearing problems (rare);
pancreatitis - severe pain in your upper stomach spreading to your back, nausea and vomiting; or
liver problems - loss of appetite, stomach pain (upper right side), tiredness, easy bruising or bleeding, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).
Serious side effects may be more likely in older adults, including hearing loss, or a life-threatening fast heart rate.
Call your doctor if a baby using this medicine is vomiting or irritable with feeding.
Common erythromycin side effects may include:
severe stomach pain, diarrhea that is watery or bloody (even if it occurs months after your last dose);
liver problems; or
abnormal liver function tests.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
 Erythromycin side effects (more detail)
