This chapter, written for undergraduate medical students and post-graduate doctors in training, presents information on how to manage red eye — a case which they are likely to encounter in the future in a general practice setting. It presents the case of a 23-year-old nursery nurse who has red eyes. On examination, the general practitioner (GP) notices lateral inflammation of the conjunctivae affecting the globe of the eye and the tarsal conjunctiva lining the inside of the eyelid bilaterally. The chapter provides details of the patients' medical history and the key findings of clinical examination, together with initial investigation results data for evaluation, and helps them develop their skills of clinical reasoning. Key questions then prompt the student to evaluate the patient, and reach a decision regarding their condition and the possible treatment plan.