Post-viral fatigue syndrome is a debilitating medical condition that can leave sufferers extremely fatigued and unable to participate in daily life without significant effort. However, there are a variety of synonyms used to describe this condition, including myalgic encephalomyelitis (ME), Chronic Fatigue Syndrome (CFS), and Systemic Exertion Intolerance Disease (SEID). The term "ME" is more commonly used in Europe, while CFS is more common in the United States. Meanwhile, the term SEID is relatively new, coined by the Institute of Medicine in 2015 to reflect the more complex aspects of this illness. Regardless of the specific terminology used, individuals with post-viral fatigue syndrome require thorough and compassionate medical care to manage their symptoms and improve their quality of life.