Background: Red eye is a common complaint that a physician could face in the hospital setting. Many causes are identified to manifest as red-eye; some of them need only reassurance, others might need surgical intervention, and if not treated appropriately, it might lead to permanent loss of vision. Objective: This review aims to discuss the common causes of red eye that the physician can face in his/her career and how to approach it. Method: We searched the PubMed database looking for relevant articles to the topic using Mesh terms, "acute red eye" and "red-eye emergency." Conclusion: Proper history taking and examination will protect patients from possible vision loss. Hence, the diagnosis can range from self-remitting condition to sight-threatening diagnoses.