Sepsis affects millions of people worldwide each year. It occurs when a normal human immune response to a bacterial, viral or fungal infection becomes dysfunctional and triggers widespread inflammation that results in severe tissue damage that leads to organ failure, shock, and death. Sepsis, requires immediate treatment and has a high readmission rate for survivors. It is also one of the most expensive conditions to treat. In 2013, there were more than 1.6 million cases of sepsis in the United States with a financial cost of more than $23 billion. Sepsis was first described in antiquity, and given its current name, by the ancient Greek physician Hippocrates. Despite its long medical history, severity, and financial burden, the causes of sepsis are not well understood, and there is no standard approach to diagnosis and treatment. The definition of sepsis, the characterization of its clinical stages, and sepsis monitoring tools have changed three times in the past 25 years, most recently in March 2016. The universal adoption of this latest definition, sepsis-3, and a screening tool, qSOFA, are currently under debate in the medical community. A means to rapidly identify and treat sepsis could reduce the five million deaths due to sepsis each year worldwide. This paper reviews the evolution of the definition of sepsis and the controversy surrounding the sepsis-3 definition and the sepsis screening tool, qSOFA.