Allergic to pcn since a baby. Use ees (erythromycin ethyl succinate) instead.?

Yes. Macrolide antibiotics like ees (erythromycin ethyl succinate) will be safe. But if your allergic reaction was some time ago, you may want to consider seeing an allergist for pcn testing. Skin testing is now very accurate. You may have outgrown your pcn allergy, or may have even been misdiagnosed, which happens often.