An otherwise healthy woman at 39 weeks’ gestation during her first pregnancy was hospitalized for an elective cesarean delivery due to breech presentation. A penicillin allergy was noted in the electronic medical record, although the details of the allergic reaction were not clear at the time of her operation. Because of the reported allergy, she was given preoperative clindamycin instead of cefazolin, the antibiotic of choice. Following the cesarean delivery, mother and baby were discharged home without complication but the woman returned 2 weeks later with diarrhea positive for Clostridium difficile toxin. She was treated with oral vancomycin for 14 days but returned 3 weeks later with recurrent infection. At that time, she was hospitalized and treated with a second course of oral vancomycin for 2 weeks. Diarrhea did not recur after the second course of vancomycin treatment.