Help! I have been taking Erythromycin tablets -500mg 4 times a day-f or severe Sinus/Ear infection for a week now. I have just realised I have mistakenly taken expired tablets for last 5 days, I put them on top of cupboard when I first got them home, not realising there was a started pack of my daughters from a long time back she had for dental infection but never took... somewhow I have picked them up & been taking them instead of ones I got form chemist as they are in exact same box. Will this have done me harm??? I still have a week to go on tabs as wee prescribed for 2 weeks. I am now returning my in date ones on next dose & have thrown expired ones. Will these have harmed me??? I took last one 2 hours ago , then I realised what had happened. Be great if expert like Nurse/Doc.Pharmacist was about to reply. Thanks