Abstract
Patients undergoing thoracic surgery were allocated at random to a penicillin group who received 2 million units of crystalline penicillin twice daily started on the day before operation and continued to the 14th postoperative day, or a control group who had no prophylactic antibiotic. Post-operative mortality due to infection was 12 times less in the penicillin group than in the control group. Large doses of penicillin given prophylactically may diminish post-operative mortality due to infection even when the infections are due to so-called "penicillin-resistant" staphylococci.