Pulmonary and critical care physicians are both users and abusers of antibiotics. Whether in the clinic, on the wards, or in the ICU, antibiotics represent one of our most often used tools. The amount of antibiotics given annually in the ICU alone can be measured in gross tonnage.1 Despite the frequency with which we order antibiotics, it remains fascinating how little we know about these compounds. In fact, the history of antibiotic prescribing is a story filled with hubris. The explosion in antimicrobial resistance underscores the veracity of this observation. Recent research, however, has clearly revealed that many assumptions that underlie our approach to antibiotic use are flawed and, perhaps, dangerous.