A reader who took the online continuing medical education (CME) exam for issue 1406 (Med Lett Drugs Ther 2012; 54:101) pointed out that the first question assumed that a rash following oral administration of ampicillin would be due to allergy. Perhaps we should have mentioned in our article on penicillin allergy that late-appearing maculopapular rashes associated with oral ampicillin or amoxicillin are generally considered non-allergic and need not preclude subsequent administration of ampicillin or amoxicillin.