We report a case of probable iatrogenic vitamin K deficiency in the context of antibiotic treatment for endocarditis. The patient was initially admitted with breathlessness and treated for an exacerbation of chronic obstructive pulmonary disease. However, during this period the patient was further diagnosed with endocarditis following repeated temperature spikes. Following initiation of antibiotic treatment for endocarditis the patient was noted to become increasingly anaemic. The patient was noted to have prolonged prothrombin time despite no anticoagulants. Antibiotics have been reported to alter the gut flora causing vitamin K deficiency; thereby, resulting in coagulopathy. We give a brief overview and literature review regarding potential vitamin K deficiency in this clinical context.