The proposed research project will retrospectively review the anesthetic records over the past 5 years and identify patients who present with a history of penicillin allergy or allergy to an antibiotic in the penicillin family. The reason for that history and the facts on which that allergy are noted will be determined. Additionally, the choice of antibiotic prophylaxis will be recorded and any adverse effect to that antibiotic noted. We will also note whether appropriate timing of the antibiotic is achieved.

Inclusion Criteria:

• Patients that are labeled as penicillin or penicillin family allergic.

Exclusion Criteria:

• As neurosurgical patients routinely receive vancomycin at NCH for surgical prophylaxis, they will be excluded from the study.

Patients with a history of allergy to penicillin who required antibiotic prophylaxis prior to/during surgery.

Please note: This is a retrospective chart review so the antibiotic related adverse events listed below occurred before the study even started.